Low-Fat Apple Muffins
["3/4 c. skim milk", "1/3 c. nonfat plain yogurt", "2 egg whites", "1 whole egg", "2 tsp. vanilla", "zest of 1 lemon", "1 1/2 c. all-purpose flour", "1/3 c. dark brown sugar, firmly packed", "1 1/2 tsp. cinnamon", "1 1/2 tsp. baking powder", "1 medium apple, peeled, cored and chopped"]
["Heat oven to 375\u00b0.", "Spray bottom of 12 medium muffin cups with vegetable spray.", "In a large bowl, beat milk, yogurt, egg whites, whole egg, vanilla and lemon zest."]
["milk", "nonfat plain yogurt", "egg whites", "egg", "vanilla", "flour", "brown sugar", "cinnamon", "baking powder", "apple"]