Best Sweet Potato Casserole Recipe

I finally perfected the Best Sweet Potato Casserole with a single unexpected pantry ingredient that made me completely rethink Thanksgiving side dishes.

I never thought a side could steal the show until I made this Thanksgiving Sweet Potato Casserole. I’m kind of obsessed with the way roasted sweet potatoes almost caramelize, then fold into something that feels fancy but is stupidly simple.

There’s a crunchy top from chopped pecans and, yes, the idea of Marshmallows naturally makes some people roll their eyes, but it’s oddly perfect here. I won’t pretend it’s flawless, I even burnt it once, but that mistake taught me more than any recipe video.

If you like surprises on the dinner table, this one will make you curious.

Ingredients

• Sweet potatoes bring natural sweetness fiber vitamin A and a creamy texture when mashed.
• Butter adds richness fat for smoothness and helps carry flavors, makes it decadent.
• Brown sugar gives caramel notes and moisture lends sweetness and a soft chew.
• Chopped pecans bring crunch healthy fats and toasty flavor contrast to soft filling.
• Eggs bind the casserole add protein and help set a custard like interior.
• Milk smooths texture adds creaminess and a touch of dairy richness without overpowering.
• Marshmallows toast to golden pillowy sweetness mostly sugar but fun for holidays.

Ingredient Quantities

• 3 pounds sweet potatoes (about 4 large)
• 1/2 cup (1 stick) unsalted butter, melted
• 1/2 cup whole milk or evaporated milk
• 2 large eggs
• 3/4 cup packed light brown sugar
• 1/4 cup granulated sugar
• 1 teaspoon pure vanilla extract
• 1/2 teaspoon kosher salt
• 1 teaspoon ground cinnamon
• 1/4 teaspoon ground nutmeg
• 1/8 teaspoon ground ginger, optional
• 1 cup packed light brown sugar for topping
• 1 cup all purpose flour for topping
• 1 cup chopped pecans or walnuts for topping
• 1/2 cup cold unsalted butter, cut into small pieces for topping
• 1/4 teaspoon salt for topping
• Optional 2 cups mini marshmallows (about a 10 oz bag)

How to Make this

1. Preheat oven to 350°F and position a rack in the center; grease a 9×13-inch baking dish with butter or nonstick spray. (If you prefer to roast whole sweet potatoes for extra flavor, roast them at 400°F for 45-60 minutes first, then lower oven to 350°F.)

2. Cook the sweet potatoes until very tender: roast whole as above and scoop, or boil peeled chunks 20-25 minutes, or microwave whole potatoes 8-12 minutes turning once; drain if boiled and let cool a few minutes so you can handle them.

3. Peel (if needed) and mash the hot sweet potatoes in a large bowl until smooth, it’s okay if a few lumps remain for texture.

4. Stir in 1/2 cup melted unsalted butter, 1/2 cup whole or evaporated milk, 2 lightly beaten eggs, 3/4 cup packed light brown sugar, 1/4 cup granulated sugar, 1 teaspoon vanilla, 1/2 teaspoon kosher salt, 1 teaspoon cinnamon, 1/4 teaspoon nutmeg and 1/8 teaspoon ground ginger if using; taste quick and adjust sweetness or spices if you want.

5. Spread the sweet potato mixture evenly into the prepared 9×13 dish, smoothing the top with a spatula.

6. Make the streusel topping: in a medium bowl combine 1 cup packed light brown sugar, 1 cup all purpose flour, 1 cup chopped pecans or walnuts and 1/4 teaspoon salt; toss in 1/2 cup cold unsalted butter pieces then use a pastry cutter or your fingers to work the butter until the mixture is crumbly and clumps form.

7. Sprinkle the streusel evenly over the sweet potato layer, pressing down lightly so it adheres; reserve a handful of nuts for garnish if you want it to look pretty.

8. Bake casserole at 350°F for about 25-30 minutes, until the topping is golden and the filling is set and not too jiggly in the middle.

9. Optional marshmallow finish: if using 2 cups mini marshmallows, sprinkle them on in the last 5 minutes of baking then switch the oven to broil for 1-2 minutes to toast them, watching very closely so they don’t burn.

10. Let the casserole rest 10-15 minutes before serving so it firms up; leftovers keep covered in the fridge 3-4 days and reheat nicely in a low oven or microwave.

Equipment Needed

1. 9×13 inch baking dish, greased
2. Rimmed baking sheet for roasting whole sweet potatoes or microwave safe plate if microwaving
3. Large mixing bowl
4. Potato masher or ricer, or just a fork for mashing
5. Measuring cups and measuring spoons
6. Silicone spatula and wooden spoon for stirring and smoothing
7. Pastry cutter or two forks to make the streusel, or use your fingers
8. Chef knife and cutting board, plus a vegetable peeler if you want to peel potatoes
9. Oven mitts and a cooling rack for resting after baking

FAQ

Best Sweet Potato Casserole Recipe Substitutions and Variations

• Milk (1/2 cup whole or evaporated): swap with full‑fat coconut milk 1:1 for a richer, slightly tropical flavor, or use almond/soy milk 1:1 if you need dairy free but expect a thinner texture, or thin Greek yogurt with a splash of water (about 3/4 cup yogurt + 1/4 cup water = 1 cup milk) to keep it creamy.
• Butter in the mash (1/2 cup melted): use coconut oil 1:1 for a dairy free option, or replace half the butter with unsweetened applesauce to cut fat (texture will be softer), or use ghee if you want the buttery flavor without milk solids.
• Brown sugar (3/4 cup in filling or 1 cup for topping): swap with coconut sugar 1:1 for a less refined option, or make quick brown sugar by mixing granulated sugar with molasses (1 cup granulated + 1 tbsp molasses = about 1 cup light brown sugar), works great if you ran out.
• Pecans/walnuts for the topping (1 cup): use toasted rolled oats mixed with the flour and butter for a nut free streusel, or sunflower seeds 1:1 if you need nut free crunch, or sliced almonds 1:1 for a different nutty bite.

Pro Tips

1) Roast your sweet potatoes instead of boiling when you can, you get way more caramelized, deep flavor. If you did boil them, drain really well and press a bit with a towel so the mash isn’t watery.

2) Don’t toss the eggs straight into hot mash, or you might get tiny scrambled bits. Let the potatoes cool a few minutes or temper the eggs by whisking a small scoop of hot mash into the beaten eggs first, then stir that back in.

3) Keep the streusel butter cold and make big clumps, not dust. Cold butter = flaky crumbs that crisp up. Toast the nuts briefly first for a nuttier crunch, and save a few whole pieces to sprinkle on top.

4) Don’t overmix the filling. Mash until mostly smooth but leave a few lumps, and stir gently when adding sugar and dairy. Overworking makes the texture gluey instead of fluffy.

5) Make ahead and timing hacks: you can assemble the whole thing (minus marshmallows) a day ahead, keep covered in the fridge, then bake a little longer from cold. Reheat leftovers low and slow in a 325F oven to keep the topping crisp. If you use marshmallows, add them at the end and broil for just 1 to 2 minutes, watch it the whole time.