Streusel-topped sweet potato pie combines a creamy sweet potato custard filling with an amazing layer of crunchy brown sugar streusel. Move over, pumpkin pie, there's a new dessert in town.
In a medium bowl, combine the streusel ingredients. Using a pastry blender, cut the butter into the dry ingredients until butter is in very small pieces and the mixture is crumbly. Place in the refrigerator until needed.
Make the pie:
Preheat oven to 450°F. Place a rimmed baking sheet in the oven while it preheats.
If the pie crust is not already in a pie plate, place it in a 9-inch deep dish pie plate, trimming and crimping the edges as desired. Keep the crust cold in the refrigerator until needed.
Place the sweet potatoes, both sugars, all of the spices, salt, butter, and half of the evaporated milk in a medium saucepan. Cook over medium-low heat for about 5 minutes, whisking until butter is melted and the mixture is well blended and starts to bubble. Remove from heat.
In a medium bowl, beat together the egg yolks with the remaining evaporated milk and the vanilla. Very slowly drizzle 1 cup of the hot sweet potato mixture into the egg mixture, whisking constantly. Pour the now-warmed egg mixture into the pot with the rest of the sweet potato mixture, whisking thoroughly.
Pour pie filling into the unbaked pie crust. Top evenly with half of the streusel mixture, placing the rest into the refrigerator until needed later. Place the pie on the baking sheet in the oven and bake for 10 minutes at 450°F. After 10 minutes, reduce heat to 325°F and bake for 20 more minutes.
After 20 minutes, add the remaining streusel to the top of the pie. (This is also a good time to rotate the pie in the oven so that it bakes evenly.) Continue baking for 40-45 minutes, until the edges and center are raised and puffed and the center only shakes slightly. A sharp pairing knife or tester inserted into the center should come out clean.
Remove from oven and cool for at least 2 hours before slicing and serving. Can be served warm or chilled.
Notes
Sweet potatoes can be cooked in any way you prefer – I typically poke the whole sweet potatoes all over with a fork and microwave until cooked through. Scoop out the flesh and mash with a potato masher or fork, or run the cooked sweet potato through a food processor or puree with an immersion blender for a super smooth texture. 2 large sweet potatoes will typically yield about 2 cups of mashed potato.
If you do not have a 9-inch deep dish pie plate, you can use a regular 9-inch or 10-inch pie plate. If using a regular 9-inch pie plate, you will have extra filling – don’t try to fit it all into the crust. When using a regular (not deep dish) pie plate, you will likely need 10-15 minutes less total baking time, so your final baking time after adding the remaining streusel will be about 30-35 minutes.
If at any point you feel the edges of your pie crust are getting too dark, cover them gently with foil or a pie guard – this will prevent them from browning further while the pie finishes baking.
Pie can be stored in the refrigerator for up to 3 days.