I always remember my mom making this when we were having company. It's one of those cakes that tastes even better the longer it sits. She would cut it into squares and place it on a pretty plate and sprinkle it with powdered sugar. It was always one of my favorites. As a matter of fact, I'm having some friends over next week...I think I'll make this!!!! ;-)
In a large mixing bowl, cream the butter, sugar, eggs and vanilla.
In a separate bowl, combine the flour, salt, and baking powder.
Alternate the dry ingredients and milk into butter mixture until well blended.
Spread batter into greased 10 x 13 inch baking pan.
Spread two cans of apple pie filling over batter and sprinkle with the cinnamon.
To make the crumb topping:
Mix flour, butter, brown sugar and cinnamon with hands and shape into a ball. Pull pieces from ball and place on top of cake. Should be enough crumbs to cover the entire top of the cake. The crumbs don't need to be perfect.
Bake for 1 hour at 350 degrees.
Let cool in the oven.
Cool completely before cutting into squares. Sprinkle with powdered sugar just before serving.