Easy 7-Ingredient Sweet Potato Casserole

A holiday dinner table simply doesn’t feel complete without a warm, comforting sweet potato casserole with marshmallows. Featuring a velvety, buttery spiced sweet potato base under a layer of melted, golden-brown mini marshmallows, this dish delivers the perfect balance of cozy sweetness.

Unlike complicated holiday side dishes, this recipe skips eggs, heavy creams, and complicated steps. It is simple, foolproof, and guaranteed to be a crowd favorite among both kids and adults.

Why You’ll Love This Recipe

Pure & Wholesome Ingredients: Fresh sweet potatoes provide natural flavor and a silky texture without requiring unnecessary fillers.
Balanced Sweetness: Keeps the base lightly sweetened with brown sugar and warm cinnamon so the toasted marshmallow topping doesn’t make it overwhelmingly sweet.
Make-Ahead Friendly: Prepare the potato mash up to two days ahead to save precious oven time on busy holidays.
Crowd Pleaser: A staple side dish for Thanksgiving, Christmas, or casual autumn Sunday dinners.

Ingredients You’ll Need

Sweet Potatoes (3 lbs / ~3 large): Peeled, cubed, and boiled until tender.
Unsalted Butter (¼ cup): Melted into the warm mash for silkiness and rich flavor.
Brown Sugar (2–3 tbsp): Adds warmth and caramel depth (light or dark brown sugar both work).
Ground Cinnamon (1 tsp): Infuses warm holiday aroma.
Ground Nutmeg (a pinch, optional): Enhances the autumnal spice profile.
Salt (¼ tsp): Balances and brightens all the sweet flavors.
Mini Marshmallows (1 to 1½ cups): Creates the signature bubbly, toasted topping.

Step-by-Step Instructions

1. Cook the Sweet Potatoes

Peel the sweet potatoes and cut them into uniform cubes so they cook evenly. Place them in a large pot, cover with lightly salted water, and bring to a boil. Simmer for 15 to 20 minutes until fork-tender. Drain completely to prevent a watery texture.

2. Mash and Season

While the potatoes are steaming hot, transfer them to a mixing bowl (or back into the dry pot). Add butter, brown sugar, cinnamon, a pinch of salt, and optional nutmeg. Mash with a potato masher or electric hand mixer until smooth and creamy. Taste and tweak sweetness or spice if desired.

3. Transfer to the Baking Dish

Lightly grease an 8×8 or 9×13-inch baking dish with butter or cooking spray. Spread the mashed sweet potatoes in an even layer, smoothing out the top using a spatula so the marshmallows toast evenly.

4. Add the Marshmallows

Evenly scatter the mini marshmallows across the surface. Leave a tiny bit of breathing room between them so they puff nicely rather than fusing into a dense sheet.

5. Bake to Golden Perfection

Preheat your oven to 375°F (190°C). Bake uncovered for 15 to 20 minutes.

Baker’s Tip: Check closely around the 12-minute mark. Marshmallows can transition from beautifully toasted to scorched in just a matter of moments.

6. Rest and Serve

Remove from the oven and let rest for 5 to 10 minutes before scooping. This allows the mash to set and prevents the marshmallow layer from sliding. Serve warm.

Pro Tips & Variations

Always Choose Fresh Potatoes: While canned yams or canned sweet potatoes save a couple of minutes, fresh boiled sweet potatoes offer superior texture and natural richness.
Savory Nut Alternative: If you prefer less sweetness, swap marshmallows for chopped pecans tossed with a pinch of sea salt and melted butter.
Dairy-Free Adaptation: Replace traditional butter with dairy-free plant butter for an easy vegan-friendly option.
Storage & Leftovers: Store leftovers in an airtight container in the refrigerator for up to 4 days. Reheat gently in the oven at 325°F to restore marshmallow crispness.

Frequently Asked Questions

Can I make this sweet potato casserole ahead of time?

Yes, absolutely! You can peel, boil, mash, and season the sweet potatoes up to 2 days in advance. Transfer the mash into your prepared baking dish, cover tightly with foil or wrap, and refrigerate. When you’re ready to serve, bring the dish to room temperature, top with mini marshmallows, and bake as directed.

Can I use canned sweet potatoes or yams instead of fresh?

Fresh sweet potatoes offer the best fluffy texture and authentic flavor, but canned ones work fine in a pinch. Use two 15-ounce cans, drain the liquid completely, and reduce or omit the added brown sugar to prevent the casserole from becoming overly sweet.

Why did my marshmallows melt into a puddle instead of toasting?

Marshmallows tend to melt flat if the oven is too cool or if they are packed too densely. Baking at 375°F (190°C) with small gaps between them allows them to puff up quickly and develop that signature golden-toasted crust.

How should I store and reheat leftovers?

Store any leftovers in an airtight container in the fridge for up to 4 days. For the best texture, reheat uncovered in an oven or toaster oven at 325°F (160°C) for 10–12 minutes to help revive the toasted marshmallow crispness.

Wrapping It Up

This easy 7-ingredient sweet potato casserole proves you don’t need hours of kitchen prep to make a standout holiday side. With its silky, spice-infused potato base and nostalgic toasted marshmallow crown, it brings immediate comfort to your dinner table. Give it a bake for your next family feast, and enjoy watching it disappear in record time!