Pumpkin Pie with Pecan Streusel

Pumpkin Pie with Pecan Streusel, adapted from Bon Appetit
1 pie crust, partially baked (click here for my recipe and tutorial)
Filling:
1 16-ounce can solid pack pumpkin
1 1/2 cups half and half
3 large eggs
1/2 cup sugar
1/4 cup packed golden brown sugar
1 1/2 teaspoons ground cinnamon
1/4 teaspoons ground allspice
1/4 teaspoon ground nutmeg
1/4 teaspoon ground cloves
1/4 teaspoon salt
Topping:
1 cup all purpose flour
1/2 cup packed golden brown sugar
1/2 cup coarsely chopped pecans (about 2 1/2 ounces)
1 tablespoon finely minced crystallized ginger, optional
1 1/2 teaspoons ground ginger
1/2 cup (1 stick) unsalted butter, cut into small pieces, room temperature
Preheat oven to 350 degrees.For filling:Whisk all ingredients in large bowl until combined. Pour into partially baked, cooled pie crust. Bake until skin begins to form on filling and filling begins to set, about 50 minutes. Remove from oven. Let pie stand 10 minutes to set slightly. Maintain oven temperature.
Meanwhile, prepare topping:Mix first 5 ingredients in medium bowl. Rub in butter with fingertips until mixture begins to form small clumps. Sprinkle topping over pie. Bake until pie is set and streusel is golden brown, about 25 minutes. Transfer to rack and cool completely. Serve with whipped cream.

adapted from Bon Appetit