Blueberry Lemon Muffins

2 cups flour
½ c sugar
3 t baking powder
½ t salt
Zest of one lemon
1 egg
1 cup milk
½ c shortening or butter
1 cup frozen blueberries
Topping:
½ cup butter, melted
1 T lemon juice
½ cup sugar
Mix dry ingred. And set aside. Beat egg, milk and shortening. Stir in blueberries. Add dry ingred. And lemon zest. Stir gently to combine. Bake at 375 degrees for 20-25 minutes. Combine butter and lemon juice. While the muffins are still warm, dip the tops in the butter and lemon juice, then dip in sugar.