Blueberry muffins

2 1/2 cups flour
1 cup sugar
4 teaspoons baking powder
1 teaspoon salt
1 egg
1 cup milk
1/2 cup sour cream
3 Tablespoons melted butter
1 teaspoon lemon zest
2 cups fresh blueberries

Sift dry ingredients together.  Add the wet ingredients, mix well.  Gently fold in blueberries.  Fill lined muffin cups 2/3 full.  Bake at 400F for about 20 minutes.  Let rest for 5 minutes before removing from pan to cool on wire rack.