Heat oven to 350 degrees. Bake crust 5 minutes.In a bowl, combine flour, baking powder, salt, and cinnamon.In the bowl of an electric mixer, cream butte and brown sugar until light and fluffy.Add eggs to butter mixture one at a time, beating until combined. Scrap down sides of bowl.Add vanilla, mix until conbined.With mixer turned to low, mix in flour mixture. Beat on low until just combined.Fold in apples by hand. Batter will be thick, much like cookie dough.Pour dough into prepared crust and spread evenly.Mix streusel: Combine sugars with cinnamon, salt and flour. Cut in butter and mix until pea-sized. I find it easier to combine using my hands to mix.Sprinkle streusel over pie and place in oven.Bake 50 to 60 minutes until brown on top and center is set.Good served warm or cold.