In a large bowl, combine pumpkin, apple butter, brown sugar, cinnamon, ginger, nutmeg, and salt. Add eggs and evaporated milk; mix until well blended. Pour into pie crust. Bake in preheated 375 degree oven for 50-60 minutes.
Crumble Topping: In a small bowl, combine 1/2 cup flour, 3 tablespoons softened butter, 5 tablespoons sugar, and 1/2 cup chopped pecans. Blend until crumbly. When using metal or foil pan, bake on a cookie sheet. When using glass, do not use cookie sheet.