In a large bowl, combine pumpkin, apple butter, brown sugar, cinnamon, nutmeg, salt, and flour. Stir in eggs and milk. Pour into prepared pie shell. Bake 50-60 minutes at 375-degrees or until a knife inserted in the center comes out clean. Sprinkle with streusel topping and bake an additional 15 minutes.

Streusel Topping:

3 tablespoons butter
1/2 cup all-purpose flour
1/3 cup brown sugar
1/2 cup chopped pecans

Mix butter, flour, and brown sugar in a small bowl until the mixture resembles coarse crumbs. Stir in nuts.