Blueberry Muffins

1/2 c. margarine

1 c. sugar

2 large eggs

1 tsp. vanilla

2 tsp. baking powder

1/4 tsp. salt

2 1/2 c. fresh or frozen blueberries

2 c. flour

1/2 c. milk

Mix butter until creamy. Add sugar and beat until pale and fluffy. Add eggs, one at a time. Beat in vanilla, baking powder and salt. Fold in half of flour, then half of milk into batter. Repeat. Fold in blueberries. Spoon into muffin cups. Bake 20-30 minutes at 375 degrees, until golden brown.