Heat oven to 350 degrees F. Lightly spray a 9-inch baking pan or dish with nonstick cooking spray. Combine flour, oats, baking powder, cinnamon, and salt. Blend with a wire whisk and set aside.
Beat together margarine and sugar. Blend in egg. Add flour mixture, applesauce, and water. Mix well. Fold in nuts and spread evenly in prepared baking dish. Bake 40 to 45 minutes or until golden brown. Cool completely. Cut into 12 squares.