Preheat oven at 350. Prepare a 12-cup Bundt Pan with cooking spray and flour.

To prepare batter, combine flour, 1 3/4 cup brown sugar, cinnamon, baking powder, baking soda, and salt in a mixing bowl.

In another mixing bowl, combine 3/4 cup margarine, 2 teaspoons vanilla, egg whites, and apples

Mix dry ingredients with wet ingredients just until moistened. Pour batter into prepared pan.

Bake for 45 minutes. Then cool upright for 30 minutes; invert onto serving plate.

Meanwhile, to prepare topping, combine powdered sugar, remaining margarine, brown sugar, remaining vanilla, and milk. Immediately spoon over cooled cake.