The Ultimate Oatmeal Cookie Sweet Potato Casserole: A Thanksgiving Dessert Side Dish
Prepare to elevate your holiday feast with this extraordinary Oatmeal Cookie Sweet Potato Casserole! This isn’t just another sweet potato dish; it’s a harmonious symphony of classic fall flavors, all magically combined in one delightful pan. Imagine the creamy richness of traditional sweet potato casserole meeting the comforting chewiness of an oatmeal raisin cranberry cookie, topped with gooey, golden marshmallows. It’s truly the best of both worlds – a sweet side dish that doubles as a festive dessert, perfect for accompanying all your savory Thanksgiving dishes or any special fall gathering.
Why This Oatmeal Cookie Sweet Potato Casserole Is a Must-Try
This Sweet Potato Casserole recipe takes a beloved holiday staple and transforms it into something truly special. Forget the ordinary; this dish is designed to be the one everyone talks about! It features a luscious, perfectly seasoned sweet potato base, crowned with a layer of fluffy marshmallows that melt into a sweet, gooey blanket. But the real showstopper? The incredible oatmeal raisin cranberry cookie crust that adds an irresistible chewiness and a burst of autumnal spices and fruit. It’s like enjoying a warm, spiced sweet potato pie with a fantastic cookie topping – pure culinary genius!
The inspiration for this unique creation comes partly from my cherished Oatmeal Raisin Cranberry Cookies recipe. I’ve incorporated the essence of those beloved cookies into a crumbly, flavorful topping that perfectly complements the rich sweet potato. To add another layer of texture and depth, I’ve included 1/4 cup of chopped pecans, which provide a subtle, nutty crunch that marries beautifully with the sweet potatoes and the oatmeal cookie notes. If pecans aren’t your preference, you can easily substitute them with an equal amount of walnuts, or simply omit the nuts altogether for a nut-free version. However, I highly recommend the pecans; they truly enhance the casserole with their delicate flavor and satisfying bite.
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Ingredients for Your Decadent Oatmeal Cookie Sweet Potato Casserole
Oatmeal Raisin Cranberry Cookie and Marshmallow Topping
This topping is what sets our casserole apart, offering a delightful contrast in texture and a burst of warm, spiced flavors. When gathering your ingredients, ensure your butter is truly soft and at room temperature for the best creamy consistency.
- ½ cup (1 stick) PLUS 6 tablespoons butter, softened. Really soft, room temperature butter is key for a smooth cookie dough.
- ¾ cup brown sugar, packed. This adds moisture and a rich, molasses flavor to the crust.
- ½ cup granulated sugar. For that extra touch of sweetness and crispness.
- 2 large eggs. Ensure they are at room temperature to emulsify properly with the butter and sugar.
- 1 teaspoon vanilla extract. A staple for enhancing all the sweet notes.
- 1-1/2 cups all-purpose flour. The base for our delicious cookie crust.
- 1 teaspoon baking soda. Helps the cookies spread and become tender.
- 1 teaspoon ground cinnamon. The quintessential fall spice that ties everything together.
- ½ teaspoon kosher salt. Balances the sweetness and brings out other flavors.
- 3 cups old-fashioned whole oats. Provides that classic chewy oatmeal cookie texture.
- ½ cup dried cranberries. Adds a lovely tartness and chewy fruitiness.
- ¼ cup pecans, chopped. Delivers a subtle, nutty crunch. Feel free to substitute with walnuts or omit for a nut-free option.
- 1 (10 ounce) bag mini-marshmallows. These will melt beautifully into a gooey layer. If you only have regular-sized marshmallows, simply cut them into smaller pieces.
Sweet Potato Casserole Filling
This creamy, flavorful base is the heart of our casserole. Using freshly cooked sweet potatoes ensures the best texture and taste.
- 5 cups (about 6 large) cooked sweet potatoes. Mash them until smooth, ready for mixing.
- Butter for greasing a 13” x 9” x 2” oven-safe baking pan. This prevents sticking and adds flavor.
- 2 large eggs. Helps bind the sweet potato mixture and adds richness.
- 1 teaspoon vanilla extract. Enhances the natural sweetness of the potatoes.
- ½ cup milk (can substitute cream or half and half). For a rich, creamy consistency. Adjust based on your desired creaminess.
- 4 tablespoons (½ stick) butter. Adds a luscious, buttery flavor to the filling.
- Optional: up to 1 cup of sugar. This is entirely dependent on the natural sweetness of your sweet potatoes. Taste your cooked sweet potatoes first; if they’re naturally very sweet, you might not need much, if any, added sugar.
Pro Tips for the Best Oatmeal Cookie Sweet Potato Casserole
Achieving sweet potato casserole perfection is easier with a few insider tips. Follow these suggestions to ensure your dish is a showstopper every time:
- Prep Ahead for Stress-Free Holidays: To make your holiday cooking much smoother, consider preparing the oatmeal cookie topping and mashing the sweet potatoes a day in advance. Store the cookie dough covered in the refrigerator and the mashed sweet potatoes in an airtight container. This way, assembly on the day of serving is a breeze!
- Baking Sweet Potatoes Like a Pro: When baking your sweet potatoes, you can place them directly on the oven rack. If you’re worried about any drips or want easier cleanup, simply line a baking sheet with foil and place them there. Remember to thoroughly wash the sweet potatoes and pierce them several times with a fork before baking to allow steam to escape and prevent them from bursting.
- Sweet Potato Baking Time Varies: The baking time for sweet potatoes can fluctuate significantly based on their size and density. I typically start by setting my oven to 350 degrees F and baking for about 1 hour. To test for doneness, gently poke a fork into the largest sweet potato. It should slide in and out with very little resistance. If you feel any firmness, they need more time. If you have a mix of sizes, remove the smaller, cooked ones and continue baking the larger ones until tender.
- Precision in Measurement is Key: This recipe is designed to fill a 13″ x 9″ x 2″ baking pan perfectly. It’s crucial to measure the 5 cups of mashed sweet potatoes and all other ingredients accurately to ensure the casserole fits and cooks evenly. If you’re using a slightly smaller pan or are concerned about overflow, place a cookie sheet underneath your baking pan to catch any potential drips.
- Achieving the Perfect Crispy Crust: The total baking time for the assembled casserole is usually around 40 minutes at 350 degrees F. However, you might find it’s perfectly done around the 30-minute mark, depending on your oven and your preference for the cookie crust. For an extra crispy oatmeal cookie topping, I recommend baking for the full 40 minutes, with an optional foil tent placed loosely over the top for the last 10 minutes. This prevents the topping from browning too much while allowing the cookie to crisp up beautifully. Always ensure that each layer of ingredients is spread evenly in the pan for consistent baking results.
- Allow Cooling Time: While it’s tempting to dig in immediately, allowing the casserole to cool for at least 10-15 minutes after baking helps it set and makes for easier, cleaner serving.
Essential Kitchen Tools for Your Casserole
Having the right tools can make all the difference in preparing this delightful dish. Here are the items you’ll want to have on hand:
- Baking Pan: A 13″ x 9″ x 2″ oven-safe baking pan is the standard size for this recipe. If you happen to have a 13″ x 9″ x 3″ pan, that’s even better, as it provides a bit more room for all the generous layers. With the 2-inch deep pan, the ingredients will come close to the top edge, but as long as everything is measured precisely and spread evenly, it should fit. As mentioned, a cookie sheet placed underneath can catch any potential spills.
- Electric Mixer: An electric hand mixer or a stand mixer will be incredibly helpful for this recipe. I personally found that a sturdy hand mixer provided ample power to efficiently blend both the creamy sweet potato filling and the rich oatmeal cookie crust to the perfect consistency.
- Large Mixing Bowls: You’ll need at least two large mixing bowls – one for preparing the sweet potato filling and another for the oatmeal cookie topping. This allows for easy mixing and organization.
- Baking Spatula: A good quality baking spatula is essential for greasing your pan, scraping down the sides of your mixing bowls, and evenly spreading the sweet potato and cookie dough layers.
These simple tools will ensure a smooth and enjoyable cooking experience as you create this incredible casserole.
The Irresistible Aroma and Final Thoughts
As your Oatmeal Cookie Sweet Potato Casserole bakes, your home will be filled with the most incredible, comforting aroma. The blend of cinnamon, sweet potatoes, and toasted oats is simply divine, creating an inviting atmosphere that perfectly captures the essence of fall and the holiday season. It’s an experience for all the senses!
This casserole is a true crowd-pleaser, balancing the savory undertones of sweet potato with the indulgent sweetness of marshmallows and a cookie topping. It’s the kind of dish that disappears quickly from the holiday table, leaving everyone asking for the recipe. I genuinely hope you and your family enjoy this sweet and utterly delicious casserole as much as my family and I do!
Enjoy every delightful spoonful!
More Irresistible Side Dishes You Might Love:
Looking to round out your holiday menu or simply find new favorites? Here are some other fantastic side dishes to explore:
- Potatoes Au Gratin with Bacon & Leeks: A beloved classic, elevated! This creamy, cheesy potato dish becomes even more irresistible with the savory addition of crispy bacon and tender leeks. It’s a crowd-pleaser that will have everyone asking for seconds.
- Irresistible Cast Iron Skillet Roasted Potatoes: If you’re a fan of crispy, flavorful potatoes, these are a must-try. Roasted in a cast iron skillet and infused with a savory broth, they achieve a perfect golden-brown exterior and a tender interior that’s truly hard to resist.
- Classic Stuffing with Parsley, Sage, Rosemary & Thyme: While often associated with Thanksgiving, a good stuffing (or dressing, as some call it!) is a delicious accompaniment to poultry any time of year. My recipe, featuring the aromatic blend of parsley, sage, rosemary, and thyme (a nod to a classic song!), is deeply flavorful and perfectly moist.
- Vibrant Spanish Rice with Black Beans and Corn: Add a touch of Southwestern flair to your dinner table with this colorful and hearty Spanish rice. Packed with robust flavors from black beans and sweet corn, it’s a versatile side dish that pairs well with a variety of main courses.
And for another delicious way to enjoy sweet potatoes, don’t miss these Sweet Potato Oat Cookies! These “healthier” cookies are a perfect treat, especially for holiday cookie exchanges, allowing you to indulge in a chocolatey delight with a little less guilt.
Oatmeal Cookie Sweet Potato Casserole
IMPORTANT – There are often Frequently Asked Questions within the blog post that you may find helpful. Simply scroll back up to read them!
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Ingredients
- Oatmeal Raisin Cranberry Cookie and Marshmallow Topping:
- ½ cup 1 stick PLUS 6 tablespoons butter, softened, I prefer really soft, room temperature butter
- ¾ cup brown sugar
- ½ cup granulated sugar
- 2 large eggs
- 1 teaspoon vanilla
- 1-1/2 cups all-purpose flour
- 1 teaspoon baking soda
- 1 teaspoon ground cinnamon
- ½ teaspoon kosher salt
- 3 cups old-fashioned whole oats
- ½ cup dried cranberries
- ¼ cup pecans chopped
- 1 10 ounce bag mini marshmallows
- Sweet Potato Filling:
- 5 cups about 5-6 large cooked sweet potatoes, mashed
- butter for greasing 13” x 9” x 2” oven-safe baking pan
- 2 large eggs
- 1 teaspoon vanilla extract
- ½ cup milk can substitute cream or half and half
- 4 tablespoons ½ stick butter
- Optional: up to 1 cup of sugar *depending on sweetness of sweet potatoes you can taste test the sweet potatoes after they are baked and cooled
Before You Begin
When you are baking the sweet potatoes you can just bake them on the wire rack or on a foil-lined baking sheet if you don’t want any drips in the oven. Make sure you wash and stab the sweet potatoes with a fork before baking.
The baking time can really vary for the sweet potatoes because the varying size of sweet potatoes. I usually set the timer for 1 hour (at 350 degrees F) and poke a fork in them to test. The fork should go in and come out easily and if there’s any resistance they need more time. You might have some smaller ones that are done and larger ones that need more time, so just leave the ones that need more time in and check periodically until fully cooked.
Make sure you measure the 5 cups of sweet potatoes and the other ingredients exactly because you will need the entire volume of the pan for this recipe. You can bake the casserole over a cookie sheet if you are concerned about drips.
The casserole’s total baking time is 40 minutes but it’s possible that it will be done at 30 minutes depending on preference. I add an extra 10 minutes, with an optional foil tent to get a really crispy oatmeal cookie crust you you might prefer something different. Make sure all the ingredients at every layer are evenly distributed to ensure even baking.
Instructions
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Prepare the Sweet Potatoes: Preheat your oven to 350 degrees F (175 degrees C). Wash and pierce the sweet potatoes several times with a fork. Bake them directly on the oven rack or on a foil-lined baking sheet for 1 hour, or until they are completely tender when pierced. Allow them to cool completely before peeling and mashing. This step can be done the day before to save time.
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Prepare the Baking Pan: Lightly grease a 13” x 9” x 2” oven-safe baking pan with butter. Set aside.
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Make the Oatmeal Cookie & Marshmallow Topping: Ensure all ingredients, especially butter and eggs, are at room temperature. In a large mixing bowl, using an electric hand mixer or stand mixer, beat the softened butter, brown sugar, and granulated sugar together on medium speed until the mixture is light, fluffy, and creamy (about 2-3 minutes). In a separate small mixing bowl, whisk together the all-purpose flour, baking soda, ground cinnamon, and kosher salt until well combined. Gradually add the dry ingredients to the creamed butter mixture, mixing on low speed until just combined. Next, beat in the 2 eggs and vanilla extract until fully incorporated. Finally, fold in the old-fashioned oats, dried cranberries, and chopped pecans (if using) until evenly distributed. Do not overmix.
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Assemble the Sweet Potato Filling: Once the sweet potatoes are completely cooled, peel them and measure exactly 5 cups of mashed sweet potatoes into a large mixing bowl. Add the remaining 2 eggs, ½ cup milk (or cream/half and half), 4 tablespoons of butter, and 1 teaspoon of vanilla extract. If desired, add up to 1 cup of sugar, adjusting to your taste preference based on the natural sweetness of your potatoes. Mix until smooth and well combined.
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Layer and Bake: Spread the sweet potato mixture evenly into the prepared 13″ x 9″ x 2″ baking pan. Next, arrange the mini-marshmallows in an even layer over the sweet potato, gently pressing them down slightly. Finally, carefully dollop spoonfuls of the oatmeal cookie dough over the marshmallows and spread it out evenly to form the top crust. As an alternative, you can reserve half of the mini-marshmallows to scatter on top of the cookie layer during the last 10 minutes of baking for a beautifully toasted marshmallow finish. Bake the casserole on the middle rack of your preheated 350 degrees F (175 degrees C) oven for 30 minutes. After 30 minutes, check the casserole. If the top is browning too quickly, loosely tent the casserole with aluminum foil. Continue baking for an additional 10 minutes, for a total baking time of 40 minutes, to ensure a perfectly golden and crispy oatmeal cookie crust.
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Cool and Serve: Once baked, remove the casserole from the oven and allow it to cool for at least 10 to 15 minutes before serving. This cooling period helps the casserole set, making it easier to serve clean slices. Enjoy this incredibly delicious and comforting dish!
The recipes on this blog are tested with a conventional gas oven and gas stovetop. It’s important to note that some ovens, especially as they age, can cook and bake inconsistently. Using an inexpensive oven thermometer can assure you that your oven is truly heating to the proper temperature. If you use a toaster oven or countertop oven, please keep in mind that they may not distribute heat the same as a conventional full sized oven and you may need to adjust your cooking/baking times. In the case of recipes made with a pressure cooker, air fryer, slow cooker, or other appliance, a link to the appliances we use is listed within each respective recipe. For baking recipes where measurements are given by weight, please note that results may not be the same if cups are used instead, and we can’t guarantee success with that method.
Recipe Attribution
This recipe is partly inspired by the wonderful Sweet Potato Casserole with Pecan Topping from Add a Pinch and my own Oatmeal Raisin Cranberry Cookies by Life’s Little Sweets, melding the best elements into this unique creation.
