Blueberry Muffins

1 & 3/4 cups all purpose flour
2/3 cup sugar
1 tbsp baking powder
3/4 tsp salt
6 tbsp butter, softened
1 egg
1/2 cup milk
1 tsp grated lemon peel
1/2 tsp vanilla extract
1 cup fresh or frozen blueberries

1. Preheat oven to 400 degrees F.  Grease 6 muffin cups.
2. In large bowl, mix flour, sugar, baking powder and salt.  Cut in butter until mixture resembles fine crumbs.
3. In small bowl beat egg, milk, lemon peel and vanilla extract until blended.  Stir egg mixture into flour mixture until flour is moistened (batter will be lumpy.)  Fold blueberries into batter.
4. Spoon batter into muffin cups.  Bake 20 to 25 minutes in preheated oven until golden and toothpick comes out clean.  Immediately serve or cool on wire rack.