This Southern Sweet Potato Casserole is silky, warmly spiced, and crowned with a buttery pecan streusel plus optional toasted marshmallows. It is the cozy, crowd-pleasing side that steals the holiday spotlight, yet it is simple enough for Sunday supper. With make-ahead tips and step-by-step guidance, you will pull it off without stress.
Why You’ll Love This Southern Sweet Potato Casserole
- Ultra creamy base with just-right sweetness and warm spice.
- Crunchy pecan streusel and optional gooey marshmallows for texture contrast.
- Make-ahead friendly and easy to transport for potlucks.
- Reliable, tested method that bakes up perfectly set every time.
Southern Sweet Potato Casserole Ingredients & Substitutions
For the sweet potato base
- 3 lb sweet potatoes (about 6 medium; 1.4 kg)
- 6 tbsp unsalted butter, melted
- 1/3 cup light brown sugar, packed
- 2 tbsp granulated sugar
- 1/2 cup milk or half-and-half
- 2 large eggs, lightly beaten
- 2 tsp pure vanilla extract
- 1 tsp ground cinnamon
- 1/4 tsp ground nutmeg
- 1/2 tsp fine sea salt
- Optional: 1 tsp orange zest for brightness
For the pecan streusel
- 1/2 cup all-purpose flour
- 1/2 cup light brown sugar, packed
- 1/2 tsp ground cinnamon
- 1/4 tsp fine sea salt
- 4 tbsp cold unsalted butter, cubed
- 1 cup chopped pecans
- Optional finish: 2 cups mini marshmallows
Easy substitutions
- Dairy-free: use canned coconut milk or almond milk and plant butter.
- Gluten-free: swap a 1:1 gluten-free flour blend or oat flour in streusel.
- Nut-free: skip pecans and use 3/4 cup oats plus 1/4 cup pumpkin seeds.
- Egg-free: use 2 flax eggs (2 tbsp ground flax + 6 tbsp water) or 2 tbsp cornstarch. Texture will be slightly softer.
- Lower sugar: reduce both sugars in the base by 1 to 2 tbsp each.
Step-by-Step Instructions to Make Southern Sweet Potato Casserole
1. Cook the sweet potatoes
Roast for deepest flavor: Heat oven to 400°F. Pierce potatoes, place on a lined sheet, and roast 45 to 60 minutes until very tender. Or boil: peel and cube, simmer in salted water 15 to 20 minutes until fork-tender, then drain well.
2. Mash and mix the base
Cool until safe to handle, peel if roasted, then mash to about 4 cups. Stir in melted butter, brown and granulated sugar, milk, beaten eggs, vanilla, cinnamon, nutmeg, and salt until creamy. Do not overmix.
3. Make the pecan streusel
In a bowl, combine flour, brown sugar, cinnamon, and salt. Cut in cold butter with a pastry cutter or fingertips until sandy with pea-size clumps. Fold in pecans.
4. Assemble the casserole
Heat oven to 350°F. Grease a 9×13-inch baking dish. Spread the sweet potato mixture evenly in the dish. Sprinkle streusel over the top in an even layer.
5. Bake to golden perfection
Bake 25 to 30 minutes until the edges are set and the topping is lightly golden. For marshmallows, scatter them on top during the last 5 to 8 minutes and watch closely until toasted to your liking.
6. Rest and serve
Let the casserole rest 10 to 15 minutes so it sets cleanly for scooping. Serve warm.
Tips for Success
- Roast if you can: roasting concentrates flavor and reduces water for a silkier base.
- Steam off moisture: if you boiled, return potatoes to the hot pot for 1 to 2 minutes to dry before mashing.
- Beat eggs first: whisk eggs separately, then stir in gently to avoid gluey texture.
- Keep butter cold for streusel: cold butter gives those craveable crunchy clumps.
- Make ahead smart: assemble the base and store; add streusel just before baking for best crunch.
Variations of Southern Sweet Potato Casserole
- Marshmallow-only topping: skip streusel and cover with marshmallows during the last 8 minutes.
- Praline topping: add 2 tbsp heavy cream to streusel for a candied finish.
- Maple bourbon twist: swap 2 tbsp milk for maple syrup and add 1 tbsp bourbon to the base.
- Savory spin: reduce sugars by half, add 1/2 tsp smoked paprika, and top with buttered panko.
- Coconut pecan: add 1/2 cup shredded coconut to the streusel.
Serving Suggestions: What to Pair with Southern Sweet Potato Casserole
- Classic proteins: roasted turkey, glazed ham, or herb-roasted chicken.
- Greens: garlicky green beans, roasted Brussels sprouts, or braised collards.
- Bright sides: tart cranberry sauce or a crisp apple salad to balance richness.
- Sweet finish: serve leftovers with vanilla ice cream for dessert.
Storage & Reheating Instructions
Refrigerator: Cool completely, cover, and refrigerate up to 4 days.
Reheat: Warm the whole dish at 325°F for 15 to 20 minutes, loosely covered. Recrisp streusel by uncovering for the last 5 minutes. Single servings reheat well in the microwave for 45 to 60 seconds.
Make ahead: Assemble the sweet potato base up to 2 days ahead. Refrigerate the base in the baking dish and keep streusel in a separate container. Add streusel and bake day of. To freeze, wrap the baked and cooled casserole tightly for up to 2 months; thaw overnight and reheat at 325°F.
Memories Made Around the Table
My aunt kept a tiny dish of toasted marshmallows off to the side so kids could sprinkle their own. The sound of spoons tapping the 9×13 and the cinnamon in the air is how I know the holidays have arrived.
FAQs
Can I use canned yams instead of fresh sweet potatoes?
Yes. Drain very well and measure 4 cups mashed. Reduce the brown sugar in the base by 1 to 2 tablespoons since canned yams are often packed in syrup.
How do I keep the casserole from turning watery?
Roast instead of boil when possible, or dry boiled potatoes briefly in the hot pot. Avoid adding extra liquid, and let the baked casserole rest before serving.
What if I cannot eat nuts?
Use an oat streusel or top with marshmallows only. For extra crunch, add pumpkin seeds or toasted coconut instead of pecans.
Can I make it vegan?
Yes. Use plant milk and plant butter, and replace eggs with 2 flax eggs. Texture will be a bit softer but still sliceable.
How do I scale the recipe?
For a 9×9-inch pan, make about two-thirds of the recipe. For a crowd, double and bake in two 9×13-inch dishes, rotating pans halfway through.
Final Thoughts
This Southern Sweet Potato Casserole brings creamy comfort and festive crunch to any table. Prep it ahead, toast those marshmallows to perfection, and watch it disappear spoonful by spoonful.
Southern Sweet Potato Casserole with Pecan Streusel
Equipment
- 1 9x13 inch baking dish
- 1 Baking Sheet lined
- 1 Large Pot optional, for boiling method
- 1 Mixing Bowls
- 1 Potato masher
- 1 Pastry cutter optional
Ingredients
For the sweet potato base
- 3 lb sweet potatoes about 6 medium; 1.4 kg
- 6 tbsp unsalted butter melted
- 0.33 cup light brown sugar packed
- 2 tbsp granulated sugar
- 0.5 cup milk or half-and-half
- 2 large eggs lightly beaten
- 2 tsp pure vanilla extract
- 1 tsp ground cinnamon
- 0.25 tsp ground nutmeg
- 0.5 tsp fine sea salt
- 1 tsp orange zest optional, for brightness
For the pecan streusel
- 0.5 cup all-purpose flour
- 0.5 cup light brown sugar packed
- 0.5 tsp ground cinnamon
- 0.25 tsp fine sea salt
- 4 tbsp unsalted butter cold, cubed
- 1 cup pecans chopped
- 2 cup mini marshmallows optional finish
Instructions
Cook the sweet potatoes
- Roast for deepest flavor: Heat oven to 400°F (200°C). Pierce potatoes, place on a lined sheet, and roast 45 to 60 minutes until very tender. Or boil: peel and cube, simmer in salted water 15 to 20 minutes until fork-tender, then drain well.
Mash and mix the base
- Cool until safe to handle, peel if roasted, then mash to about 4 cups. Stir in melted butter, brown and granulated sugar, milk, beaten eggs, vanilla, cinnamon, nutmeg, and salt until creamy. Do not overmix.
Make the pecan streusel
- In a bowl, combine flour, brown sugar, cinnamon, and salt. Cut in cold butter with a pastry cutter or fingertips until sandy with pea-size clumps. Fold in pecans.
Assemble the casserole
- Heat oven to 350°F (175°C). Grease a 9x13-inch baking dish. Spread the sweet potato mixture evenly in the dish. Sprinkle streusel over the top in an even layer.
Bake to golden perfection
- Bake 25 to 30 minutes until the edges are set and the topping is lightly golden. For marshmallows, scatter them on top during the last 5 to 8 minutes and watch closely until toasted to your liking.
Rest and serve
- Let the casserole rest 10 to 15 minutes so it sets cleanly for scooping. Serve warm.