Preheat oven to 400 degrees. Prepare or thaw the 9 inch pie crust and set aside.
In a large bowl, whisk eggs until yolk and whites are combined. Add pumpkin, apple butter, sugar, salt, cinnamon, ginger, and nutmeg. Combine well.
Stir in half and half. Pour mixture into pie shell and bake in oven 10 minutes. Reduce heat to 350 degrees and continue baking an additional 35-40 minutes, or until a knife comes out clean from center. Allow to cool for 30 minutes at room temperature, then transfer to refrigerator.
Prepare streusel/crumble by combining flour, light brown sugar, cinnamon and salt in a bowl. Using a cheese grater, grate very cold butter into small pieces directly onto flour mixture. Rub between your hands to turn streusel into small lumps.
Stir in pecans. Spread evenly onto a lined cookie sheet and bake at 350 for about 10 minutes, or until golden brown. When cooled, store in a plastic bag. Sprinkle topping generously on top of pie before serving!!