Preheat oven to 325°. In a large bowl, combine dry cake mix, egg whites, sour cream and applesauce. Beat on low speed until moistened. Beat on medium for 2 minutes. , Pour half into a greased 13x9-in. baking pan. Combine brown sugar and cinnamon; sprinkle over batter. Cover with remaining batter; cut through with a knife to swirl. Bake until a toothpick comes out clean, 35-40 minutes. Cool on a wire rack., For glaze, combine confectioners' sugar, milk and vanilla until smooth; drizzle over warm cake.