This is a cozy, creamy sweet potato casserole made entirely in the slow cooker. The sweet potatoes cook slowly until tender, are mashed with butter, sugar, spices, and topped with a crunchy pecan‑butter mixture (and optionally marshmallows) for a warm, comforting side dish.
Why You’ll Love This Recipe
I love this recipe because it’s mostly hands‑off once it’s going, it doesn’t hog oven space during a big meal, and the contrast between smooth sweet potatoes and crunchy topping always wins over my family. The slow cooker helps deepen the flavors over time, and I can prep much of it ahead of time.
ingredients
(Here’s a tip: Check out the full list of ingredients and measurements in the recipe card below.)
For the sweet potato base
4 lb (approx. 1.8 kg) sweet potatoes, peeled and cut into 1‑inch (2.5 cm) cubes
½ cup (100 g) dark brown sugar
¼ cup (60 g) unsalted butter, melted
1 tablespoon vanilla extract
1 tablespoon water
1 teaspoon ground cinnamon
1 teaspoon pumpkin pie spice
½ teaspoon salt
For the topping
3 tablespoons brown sugar
2 tablespoons unsalted butter, melted
2 tablespoons chopped pecans (toasted)
Optional (classic finish)
2 cups mini marshmallows
Additional ½ cup pecans for sprinkling
directions
Place the peeled and cubed sweet potatoes into the bowl of the slow cooker.
In a separate bowl, whisk together the ½ cup brown sugar, ¼ cup melted butter, vanilla extract, water, cinnamon, pumpkin pie spice, and salt until well combined.
Pour that mixture over the sweet potatoes in the slow cooker, then gently stir so that the cubes are evenly coated.
Cover and cook:
On High for 3½ to 4 hours, or
On Low for 6 to 8 hours, or until the sweet potatoes are fork‑tender.
Once tender, use a potato masher or a handheld mixer to mash the sweet potatoes right in the slow cooker to your desired consistency (some slightly chunky is nice).
In a small bowl combine the topping ingredients: 3 tablespoons brown sugar, 2 tablespoons melted butter, and 2 tablespoons chopped pecans.
Sprinkle that topping evenly over the mashed sweet potatoes.
If you’re using marshmallows and extra pecans, sprinkle them on top now. Cover again and let cook on High for another 10–15 minutes, until the marshmallows are melted (note: they won’t brown much in the slow cooker) and the topping is set.
Serve warm, directly from the slow cooker or transferred to a serving dish (sprinkle extra pecans just before serving if desired).
Servings and timing
Servings: about 8 to 10 side‑dish servings
Prep time: ~15 minutes
Cook time: 3½ to 4 hours on High, or 6 to 8 hours on Low
Additional topping melt time: 10–15 minutes
If I’m short on time, I use High. If I set it early in the day, I use Low and let it go while working on other dishes.
Variations
No nuts version: Simply omit pecans or substitute with chopped walnuts.
Dairy‑free / vegan: Use plant‑based butter and a nondairy milk (like almond milk) in place of butter/milk components, and skip marshmallows or use vegan marshmallows.
Spice twist: Add a pinch of nutmeg or ginger for extra warmth.
Crunchier topping: After slow cooking, transfer to an ovenproof dish, sprinkle topping, and broil briefly to brown.
Maple version: Substitute half (or all) of the brown sugar with pure maple syrup for a richer flavor.
storage/reheating
Storage: Let the casserole cool, then store in an airtight container in the refrigerator for up to 4–5 days.
Freezing: You can freeze portions for up to 2–3 months. Thaw overnight in the fridge before reheating.
Reheating:
Microwave individual portions until warm, stirring occasionally.
Or reheat in a 350 °F (175 °C) oven, covered, until heated through (about 15–20 minutes).
If topping has softened, you can add a fresh sprinkle of pecans (or marshmallows) after reheating.
FAQs
What size slow cooker should I use?
I use a 5‑ to 6‑quart (5 to 6 L) slow cooker. Anything smaller may overflow, and much larger ones simply give extra headroom.
Can I prepare this the night before?
Yes — I sometimes peel, cube, and toss the sweet potatoes with the sugar/butter mixture the night before, cover, and refrigerate. Next day I dump into the slow cooker and cook as directed.
Can I skip the topping or marshmallows?
Yes — the topping is optional. The dish is still delicious without nuts or marshmallows, especially if you prefer a simpler texture.
Why don’t the marshmallows brown in the slow cooker?
Because slow cookers don’t reach high enough temperatures to brown marshmallows (they melt, but won’t toast). If I want them browned, I move the dish under a broiler or use a kitchen torch for a minute.
How can I make the casserole thicker if it’s too runny?
I mash the potatoes well to absorb liquid. If still too loose, I sometimes stir in 1 to 2 tablespoons of flour or cornstarch mixed into a little water and cook another 10 minutes until thickened.
Conclusion
I find this slow cooker sweet potato casserole to be one of my favorite hands‑off holiday sides. It’s comforting, flavorful, and flexible. Whether I want it nutty, plain, dairy‑free, or topped with gooey marshmallows, this method adapts easily. Let me know if you’d like me to format it into a printable recipe card or scale it up for a crowd.
A cozy, creamy sweet potato casserole made in the slow cooker, featuring mashed sweet potatoes with a rich blend of spices and brown sugar, topped with a crunchy pecan topping and optional marshmallows.
Ingredients
4 lb (approx. 1.8 kg) sweet potatoes, peeled and cut into 1‑inch cubes
Place the peeled and cubed sweet potatoes into the bowl of the slow cooker.
In a separate bowl, whisk together the brown sugar, melted butter, vanilla extract, water, cinnamon, pumpkin pie spice, and salt until well combined.
Pour the mixture over the sweet potatoes in the slow cooker and gently stir to coat evenly.
Cover and cook on High for 3½ to 4 hours, or on Low for 6 to 8 hours, until the sweet potatoes are fork-tender.
Use a potato masher or handheld mixer to mash the sweet potatoes to your desired consistency.
In a small bowl, combine the topping ingredients: brown sugar, melted butter, and chopped pecans.
Sprinkle the topping over the mashed sweet potatoes.
If using marshmallows and extra pecans, sprinkle them on top now. Cover and cook on High for another 10–15 minutes until the marshmallows are melted and the topping is set.
Serve warm directly from the slow cooker or transfer to a serving dish and garnish with extra pecans if desired.
Notes
Use a 5- to 6-quart slow cooker for best results.
Make ahead by prepping sweet potatoes and spice mixture the night before.
Omit nuts or substitute with walnuts for a nut-free version.
Use plant-based butter and vegan marshmallows for a dairy-free/vegan version.
For a browned topping, transfer to ovenproof dish and broil briefly.