Preheat oven to 350. Sift together flour, baking powder, salt.

Beat egg whites and set aside

Cream butter and sugar. Add flour mixture and milk until combined. Dont overbeat.

Fold in beaten egg whites with rubber spatula. Spread in well greased 9x13 baking pan.

In separate bowl combine topping ingredients with pastry cutter until crumbly, sprinkle over top.

Bake for 40 to 45 minutes or no longer jiggly.