Miss Frances' Blueberry Surprise Cake

One summer I interned at a Wal-Mart Distribution center in South Carolina. The customer service coordinator was Miss Frances, a precious older lady who liked to bake. She brought this cake in one day, and it is to die for, I promise.

Miss Frances' Blueberry Surprise Cake

1 can blueberry pie filling (Lucky Leaf, heavy syrup)
3 c. sifted cake flour
1 tsp baking powder
1 tsp baking soda
1 c sugar
1 c butter
2 eggs, beaten
1 c sour cream
1 tsp vanilla

Topping
1/4 c. cake flour
3 tbsp butter
1/4 c sugar

Preheat oven to 375. Line a 9x13 cake pan with foil and generously grease the foil. Sift flour once. Add baking powder, soda, and sugar and sift into mixing bowl. Cut in butter until mixture resembles coarse meal. Add eggs, sour cream, and vanilla. Beat well to blend. Spread half the batter evenly in prepared pan.Spoon pie filling on top, spreading gently but evenly. Spread remaining batter over pie filling as evenly as possible. Combine flour, butter and sugar to make a crumb topping. Sprinkle evenly over batter. Bake 45 minutes. Cool in pan before serving.