Some sides quietly support the turkey. This one starts an argument about who gets the corner with the most pecan streusel. Creamy mashed sweet potatoes, brown sugar, melted butter and a little vanilla go under a crumbly pecan topping that bakes up toasted and golden. You can assemble it a day ahead and slide it into the oven on Thanksgiving, which is exactly when you want one less thing to fuss over.
Serves about 8–10 · Bake sweet potatoes 45–60 min · Bake casserole 30–35 min · Make ahead up to 1 day
Ingredients
Filling
- 3 lb sweet potatoes (about 4 medium)
- ½ cup packed light brown sugar
- 4 tablespoons unsalted butter, melted, plus more for the dish
- ½ cup warm whole milk (or half-and-half)
- 2 large eggs
- 1 teaspoon vanilla extract
- ½ teaspoon ground cinnamon
- ½ teaspoon kosher salt
Pecan streusel
- 1 cup chopped pecans
- ½ cup packed light brown sugar
- ⅓ cup all-purpose flour
- 4 tablespoons unsalted butter, melted or cubed
- Pinch of kosher salt
Instructions
- Bake the sweet potatoes. Heat the oven to 400°F. Prick the sweet potatoes and bake until they’re very tender, 45 to 60 minutes. (Or peel, cube and simmer them in water until tender, 15 to 20 minutes, then drain well.) Let them cool slightly; if you baked them whole, peel, then mash.
- Get the dish ready. Lower the oven to 350°F. Butter a 9×13-inch or similar 2- to 3-quart baking dish.
- Mash the filling. Mash or beat the sweet potatoes with the brown sugar, melted butter, warm milk, eggs, vanilla, cinnamon and salt until smooth.
- Spread it out. Spread the filling evenly in the buttered dish.
- Make the streusel. Stir the pecans, brown sugar, flour, butter and a pinch of salt until the mixture is crumbly. Sprinkle it evenly over the filling.
- Bake. Bake at 350°F until the topping is golden and the center is hot, about 30 to 35 minutes. Because the filling has eggs, the center should reach 160°F on a food thermometer.
Why it works
- Bake, then mash. Whole baked sweet potatoes keep more flavor than boiled ones, and they’re easy to peel once they cool a little. Boiling the cubes is faster if you’re short on time; just drain them well so the filling isn’t watery.
- Warm milk and melted butter. They blend into the mash without tightening it, so the casserole stays creamy.
- Eggs set the center. Two eggs give the filling enough structure to slice into squares without turning it into a custard.
- Streusel, not a heavy crust. Pecans, brown sugar, flour and butter bake into a toasted, crumbly top — the part people fight over — without hiding the sweet potatoes underneath.
- Make it a day ahead. Assemble, cover and refrigerate, then bake from cold on Thanksgiving. For the crispest topping, store the streusel separately and add it just before baking.
Make-ahead and leftovers
Assemble the casserole up to 1 day ahead, cover, and refrigerate. The topping can be stored separately for the crispest finish, then sprinkled on just before baking. Bake from cold at 350°F until the center is 160°F, adding several extra minutes as needed.
Refrigerate leftovers within 2 hours. Reheat to 165°F.
Food safety notes
This filling includes eggs, so treat it like other egg dishes: cook until a food thermometer in the center reads 160°F. The USDA FSIS Safe Minimum Internal Temperature Chart lists 160°F for eggs and 165°F for leftovers. USDA also notes that egg dishes and egg casseroles should reach 160°F; leftover portions should be reheated to 165°F.
A marshmallow variation
If someone at the table insists on marshmallows, you can skip the streusel (or use half) and add mini marshmallows for the last 8 to 10 minutes of baking, just until they’re toasted. This version keeps the pecan streusel as the main topping.
Save it for next year
This is exactly the kind of recipe that lives on a stained index card — or disappears into a text thread by next November. Keep the Sauce keeps your family’s recipes in one place, scales them to the servings you need, and shares them with the people you cook with. It’s $4.99 on iPhone & Android: keepthesauce.com.
More for the Thanksgiving table: make-ahead turkey gravy, make-ahead cranberry sauce, make-ahead sausage and herb stuffing, Cajun andouille sausage stuffing, make-ahead mashed potatoes, and how to thaw a turkey.
FAQ
Can I make this a day ahead? Yes. Assemble it up to 1 day ahead, cover, and refrigerate. For the crispest streusel, keep the topping separate and add it just before baking. Bake from cold at 350°F until the center reaches 160°F, adding a few extra minutes as needed.
Do I have to bake the sweet potatoes whole? No. Baking them whole at 400°F for 45 to 60 minutes gives a deeper flavor, but you can peel, cube and simmer them until tender, 15 to 20 minutes, then drain well before mashing.
Why 160°F? The filling has eggs. USDA lists 160°F as the safe minimum for eggs and egg dishes. Use a food thermometer in the center; leftover portions should be reheated to 165°F.
How many people does it serve? A 9×13 Thanksgiving side typically serves about 8–10.
What if I want marshmallows? Skip the streusel or use half, and add mini marshmallows for the last 8 to 10 minutes until they’re just toasted. The pecan streusel is still the main recipe here.