For the casserole:
- 3 cups mashed cooked sweet potato (about 3 medium potatoes)
- 3/4 cup granulated sugar
- 1/2 cup (1 stick) unsalted butter, melted
- 1/3 cup milk
- 1 teaspoon vanilla
- 2 eggs, beaten
For the streusel topping:
- 1 cup chopped pecans or walnuts
- 3/4 cup packed brown sugar
- 1/2 cup all-purpose flour
- 1/2 cup (1 stick) unsalted butter, softened and cut into small cubes
- Heat oven to 350 degrees F.
- In a large bowl, stir together mashed sweet potatoes, sugar, butter, milk, vanilla and eggs until well combined. Pour and spread evenly into a casserole dish.
- In a medium bowl using a pastry cutter or your fingers, combine pecans, brown sugar, flour and butter until mixture forms a coarse crumb. Sprinkle streusel evenly over top of casserole.
- Bake 40 minutes until casserole is baked through and streusel topping is golden brown and bubbling.