Apple Crisp

I got this recipe from Mom and it is my favorite for Apple Crisp.

1 cup butter, cold
1 cup brown sugar, packed
1 cup flour
1 cup oatmeal
1/4 tsp. baking powder
6 cups apples, sliced
Combine butter, sugar, flour, oatmeal and baking powder together until crumbly. Slice apples into a 9"x13" dish. Crumble the topping over the apples and bake at 350 for 45 minutes.