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This Slow Cooker Sweet Potato Casserole is proof you don’t need your oven to pull off a holiday classic. Tender sweet potatoes simmer low and slow with warm spices and brown sugar, then get finished with a buttery pecan-marshmallow topping, all right in the crock pot! It’s the easiest way to free up valuable oven space when your kitchen is already working overtime.
If there’s one dish that never leaves my Thanksgiving table, it’s sweet potato casserole. But some years my oven is already stuffed with a turkey and a pan of biscuits, so I started making this one in the crock pot instead. Honestly, it might be even better this way. Cooking the sweet potatoes low and slow gives them time to soak up all that brown sugar and molasses flavor, and the buttery pecan-marshmallow topping melts into golden, gooey perfection with barely any effort on your part.
This crockpot sweet potato casserole recipe comes together with just one bowl and a slow cooker. That’s it! I like to think of it as the lazy cousin to my Sweet Potato Pie. It’s got the same cozy flavors, but a whole lot less fuss. If you’re a fan of a good candied topping, you’ll want to check out my Candied Pecans too.
Why you’ll love this Slow Cooker Sweet Potato Casserole
❥ Frees up your oven. This casserole cooks entirely in the slow cooker, so there’s zero competition for oven space on Thanksgiving Day.
❥ Minimal hands-on effort. Outside of a quick whisk and an hourly stir, the slow cooker does all the heavy lifting for you.
❥ Make-ahead friendly. You can start this a day early and finish it right before serving, which is a lifesaver when you’re juggling a full holiday spread.
❥ Naturally gluten-free. With no flour in the mix, this casserole fits right in on a gluten-free holiday table without any substitutions needed.
❥ That topping! A buttery pecan-brown sugar crumble under melted marshmallows gives you the best of both classic casserole styles in one dish.
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Nikki’s Top Tips Before You Start
- Cut your sweet potatoes into even, 1-inch cubes. Uniform pieces cook at the same rate, so you won’t end up with mushy edges and hard centers. Take an extra minute here — it really does make a difference in the final texture.
- Stir every hour on the dot. This slow cooker sweet potato casserole recipe cooks on high, and without stirring, the sugar mixture at the bottom can scorch before the potatoes finish cooking. Set a timer so you don’t forget.
- Spray that slow cooker bowl generously. The brown sugar and butter mixture is sticky, and without a good coat of cooking spray, it will cling to the sides and burn. A few extra seconds of prep saves you a scrubbing headache later.
Ingredients
For the sweet potatoes:
- Sweet potatoes: Peel and chop into 1-inch cubes so they cook evenly and become perfectly tender.
- Light brown sugar: Adds deep, caramel-like sweetness to the sweet potato mixture.
- Salted butter: Brings richness and helps the brown sugar mixture coat the potatoes evenly.
- Molasses: Optional, but it deepens the flavor and gives the casserole that classic old-fashioned sweetness.
- Milk: Helps thin the brown sugar mixture just enough so it coats the potatoes evenly.
- Ground cinnamon, nutmeg, and cloves: The warm autumn spice trio that makes this taste like the holidays.
- Kosher salt: Balances all that sweetness! Don’t skip it.
- Vanilla extract: Rounds out the spices with a warm, cozy flavor.
For the topping:
- Mini marshmallows: The finishing touch. They get perfectly melted and gooey on top of everything.
- Light brown sugar: Creates that irresistible crumbly, caramelized topping.
- Salted butter: Binds the topping together and helps it turn golden.
- Chopped pecans: Adds crunch and a toasty, nutty flavor to contrast the soft sweet potatoes.
How To Make Slow Cooker Sweet Potato Casserole
✱ Below shows step-by-step photos and instructions. For the complete recipe, along with ingredient amounts, scroll down to the recipe card.
Step 1 | Prep the Brown Sugar Mixture
Spray a slow cooker bowl with cooking spray. In a medium mixing bowl, whisk together the brown sugar, butter, molasses, milk, cinnamon, nutmeg, cloves, salt, and vanilla.
Step 2 | Toss with Sweet Potatoes
Put all the cut sweet potatoes in the bottom of the slow cooker. Pour the brown sugar mixture over the sweet potatoes and toss to coat evenly.
Step 3 | Slow Cook
Turn on high and cover. Cook for about 4 hours, making sure to stir every hour, until the sweet potatoes are tender.
Step 4 | Mash
Mash the sweet sweet potatoes with a potato masher or an electric mixer at this point or leave them whole.
Step 5 | Make the Pecan Topping
In a mixing bowl, make the topping by whisking together the brown sugar, butter, and pecans.
Step 6 | Spread Topping on Top
Sprinkle over the top of the sweet potatoes.
Step 7 | Top with Marshmallows
Then evenly sprinkle the marshmallows over the top.
Step 8 | Melt Marshmallows & Enjoy
Put the lid back on and continue cooking on high for about 10-15 minutes longer, or until the marshmallows are melted. You can use a kitchen torch to toast the marshmallows on top, if desired.
Variations & Substitutions
- Swap the pecans for walnuts. If pecans aren’t your favorite, walnuts work just as well and give a similar crunch.
- Use large marshmallows instead of mini. Simply cut them in half or quarters so they melt and spread evenly across the top.
- Leave out the molasses. It’s optional in this recipe, so if you don’t have any on hand, you can skip it without changing the recipe much.
- Make it dairy-free. Substitute a plant-based butter and a dairy-free milk of your choice for a dairy-free version of this casserole.
- Bake it instead! If you prefer not to use the slow cooker, follow my Classic Sweet Potato Casserole recipe.
Gluten-Free
This slow cooker sweet potato casserole is naturally gluten free, since there’s no flour anywhere in the recipe. Just be sure to double-check the labels on your marshmallows and molasses, as some brands can be processed in facilities that also handle gluten-containing products.
Expert Tips
Here are my top tips I use for the best crockpot sweet potato casserole!
- Don’t be tempted to cook this on low. The sugars need the higher, steadier heat of the high setting to break down properly in the timeframe given. Low heat just doesn’t get there the same way.
- Mash or leave whole; it’s up to you. Once the sweet potatoes are fork-tender, you can mash them smooth with a potato masher or electric mixer, or leave the cubes mostly intact for a chunkier, more rustic casserole.
- Adjust the salt based on your butter. If you’re using unsalted butter instead of salted, add a touch more kosher salt to both the sweet potato mixture and a small pinch to the topping so the flavors stay balanced.
What to Serve With Crockpot Sweet Potato Casserole
Typically, I serve this slow cooker sweet potato casserole with holiday meals. I like to serve it with my Oven Roasted Turkey, a Coca Cola Ham, or an Oven Baked Garlic Herb Rump Roast. Cranberry Orange Glazed Cornish Hens are another great option when you want an elegant, individually-portioned main.
Pair it with a few additional sides like my Crock Pot Green Beans and some warm Southern Buttermilk Biscuits to soak up all those extra juices!
Storage, Make-ahead
Storage: Keep leftovers in an airtight container in the refrigerator for up to 3 to 4 days.
Freeze: This casserole is best enjoyed fresh, as the marshmallow topping doesn’t freeze and thaw well. If you’d like to freeze it, do so before adding the topping, then add the pecan mixture and marshmallows after thawing and reheating.
Make Ahead: Prepare the recipe as directed, but cook for 3 hours instead of 4. Refrigerate until about 2 hours before you’re ready to serve. Return the sweet potatoes to the slow cooker liner and cook on high for about 90 minutes, or until tender. Finish with the topping as directed.
Frequently Asked Questions
Sweet potato casserole usually turns out runny when there’s too much liquid relative to potato, often from undercooked or watery sweet potatoes, too much butter or milk in the mix, or not mashing/reducing enough before adding the topping. In this slow cooker version specifically, skipping the hourly stir or pulling it early (before the potatoes are fully fork-tender and any excess liquid has cooked down) is the most common culprit.
Fresh sweet potatoes are recommended for the best texture and flavor in this recipe. Canned sweet potatoes are softer and packed with liquid, which would throw off the texture of the finished casserole.
A 6-quart slow cooker works well for this recipe and comfortably holds 3½ to 4 pounds of sweet potatoes along with the sauce.
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Slow Cooker Sweet Potato Casserole
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Ingredients
- 3 ½- 4 pounds sweet potatoes - peeled and chopped into 1-inch cubes
- ½ cup light brown sugar
- 4 tablespoons salted butter - melted
- 1 tablespoon molasses - optional
- 1 tablespoon milk
- 1 ½ teaspoons ground cinnamon
- ¼ teaspoon nutmeg
- ¼ teaspoon ground cloves
- ¼ teaspoon kosher salt - plus more to taste
- 1 tablespoon vanilla extract
- 6 tablespoons light brown sugar
- 4 tablespoons salted butter - melted
- 6 tablespoons chopped pecans
- 1 ½ cups mini marshmallows
Instructions
- Spray a slow cooker bowl with cooking spray.
- In a medium mixing bowl, whisk together the brown sugar, butter, molasses, milk, cinnamon, nutmeg, cloves, salt, and vanilla.
- Put all the cut sweet potatoes in the bottom of the slow cooker. Pour the brown sugar mixture over the sweet potatoes and toss to coat evenly.
- Turn on high and cover. Cook for about 4 hours, making sure to stir every hour, until the sweet potatoes are tender.
- Mash the sweet sweet potatoes with a potato masher or an electric mixer at this point or leave them whole.
- In a mixing bowl, make the topping by whisking together the brown sugar, butter, and pecans. Sprinkle over the top of the sweet potatoes.
- Then evenly sprinkle the marshmallows over the top.
- Put the lid back on and continue cooking on high for about 10-15 minutes longer, or until the marshmallows are melted. You can use a kitchen torch to toast the marshmallows on top, if desired.
Notes
- If using unsalted butter instead of salted, add a bit more salt to the sweet potato mixture and a small pinch to the topping.
- Be sure to spray the slow cooker bowl well, or the sugar mixture will stick and burn.
- This recipe needs to cook on high, it won’t turn out right on low.
- Stir every hour while cooking to prevent burning on the bottom.
- Store leftovers in an airtight container in the fridge for up to 3-4 days.
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Nutrition
Soulfully Made is not a dietician or nutritionist, and any nutritional information shared is an estimate. If calorie count and other nutritional values are important to you, we recommend running the ingredients through whichever online nutritional calculator you prefer. Calories and other nutritional values can vary quite a bit depending on which brands were used.
