Cut together sugar and shortening. Sift together flour, baking powder, and salt. Combine eggs and milk. Stir together all ingredients and fold in blueberries. Pour batter into a greased and floured 9x13 inch pan. Sprinkle with topping.
Make the topping: Mix together all ingredients until crumbly in texture. Sprinkle on top of cake batter before baking. Bake at 375 degrees for 25 to 30 minutes.