Grease 12 muffin cups or line with paper cups. Set aside.
To make topping, stir together brown sugar, 1 tablespoon all-purpose flour, 1 tablespoon whole wheat flour and 1/2 teaspoon cinnamon. Cut in margarine. Stir in 1/4 cup walnuts. Set aside.
In a medium bowl combine flours, baking soda, cinnamon, sugar and salt. In a small bowl, combine apples and egg whites. Stir in nuts and applesauce with apple-egg mixture. Add wet ingredients to dry ingredients and mix to combine.
Fill muffin cups 2/3s full with batter. Sprinkle topping over each cup.
Bake in a 400 degree oven for 15-18 minutes, or until golden. Cool in pan for 5 minutes. Remove muffins from cups and serve warm.