Preheat oven to 350 degrees. Grease a 9x13 inch baking dish.
In a bowl, combine butter and sugar using a mixer. Add eggs and mix thoroughly. In another bowl, combine dry ingredients. With mixer running, add dry ingredients and milk alternately until a batter forms. Fold in blueberries with a spoon.
Pour batter into prepared pan and bake in preheated oven for 30 to 40 minutes or until a tester comes out clean. Makes 12 to 15 servings. Enjoy!