Pre-heat oven to 375. Cream butter and sugar until fluffy on low speed with electric mixer. Add eggs, one at a time, and mix until blended. Sift dry ingredients and add alternatively with milk and vanilla. Add blueberries and stir in by hand. Grease muffin tins well including top surfaces. Fill high and sprinkle tops with sugar. Bake at 375 for 30 minutes.