Topping:
1/2 cup sugar
1/4 cup all-purpose flour
1/4 cup whole wheat flour
1/4 cup butter
2 teaspoons cinnamon 

Cream the sugar and the butter in a mixer. Add the egg and mix well. Sift the dry ingredients and add them to the butter/sugar mixture, alternating with the milk. Fold in the blueberries and pour the batter into a 9 by 13-inch pan.

Topping: Combine all of the ingredients using a pastry blender or in an electric mixer with the paddle attachment. Sprinkle over the batter and bake at 375 degrees for 35 to 45 minutes.