Preheat oven to 350°F. Spray 9" x 12" baking pan with non-stick spray. In bowl stir together flour, oats, brown sugar, cinnamon and baking soda. Stir in walnuts. In small bowl, beat together apple sauce and egg white with fork. Add apple sauce mixture to oat mixture, mix with fork (mixture will be sticky). Set aside 1 cup of mixture for topping. Press remaining amount in pan to form a crust. Spread preserves on top. Drop small spoonfuls of reserved mixture over the top. Bake 25-30 minutes or until brown.