Sweet Potato Pie

Name: Sweet Potato Pie
Prep time: 25 min
Cook time: 2 h
Total time: 2 h 25 min
Cuisine: American, Southern
Ingredients: 1 c. all-purpose flour; 1/4 tsp. baking powder; 1/4 tsp. kosher salt; 6 tbsp. cold unsalted butter; c. sour cream; 1 lb. sweet potatoes; 1 c. packed dark brown sugar; 1/2 tsp. ground cinnamon; 1/2 tsp. ground allspice; 1/4 tsp. ground nutmeg; 1 tsp. salt; 4 eggs; 1 c. heavy cream; 1/4 c. butter