Apple Muffins: Decrease sugar to 1/4 cup; add 1 teaspoon ground cinnamon to flour. Stir 1 cup finely chopped, peeled apple into dry ingredients. Substitute apple juice for milk. Bake 18 to 22 minutes.
Blueberry Muffins: Stir 1 cup fresh or frozen blueberries (do not thaw) and 1 teaspoon grated lemon or orange peel into dry ingredients.
Lemon Muffins: Stir 1 tablespoon grated lemon peel into flour mixture.
Orange Muffins: Stir 1 tablespoon grated orange peel into flour mixture; substitute orange juice for milk.
Whole Wheat Muffins: Use 1 cup all-purpose flour and 1 cup whole wheat flour.