Blueberry Muffins

1/4 lb butter
1 c sugar
2 eggs
1 t vanilla
1 c flour
1 c whole-wheat flour
1 T baking powder
1/2 c milk
2 c blueberries
Sugar

Preheat oven to 375. In mixer or large bowl, cream butter and sugar. Add eggs one at a time, beating well. Add vanilla. Mix flour and baking powder. Add to bowl alternately with milk, just until mixed. Fold blueberries into batter. Spoon into well-buttered muffin pan. Bake 15 minutes then sprinkle tops of muffins with sugar; rotate pan and bake 15 minutes longer. Cool 20 - 30 minutes before removing from pan. These freeze well.