Preheat oven to 350°F. Lightly coat an 8x8x2-inch baking pan with nonstick cooking spray; dust lightly with flour. Set aside.
In a large mixing bowl, combine the 1½ cups flour, the sugar, ginger, cinnamon, baking powder, baking soda and salt. Add the water, molasses, butter and egg whites. Beat with an electric mixer on low to medium speed until combined. Beat on high speed for 2 minutes. Spread into prepared pan.
Bake in preheated oven about 20 minutes or until a wooden toothpick inserted near the center comes out clean. Cool in the pan on a wire rack for 10 minutes. Remove cake from pan. Cut into 9 squares; serve warm and, if desired, with dessert topping.
Tip: If using sugar substitutes, choose from Splenda® Sugar Blend for Baking or Equal® Sugar Lite. Follow package directions to use amount equal to ¼ cup sugar. Nutrition per serving with substitute: As below, except 160 calories, 3 g protein, 28 g carbohydrate, 4 g fat, 10 mg cholesterol, 2 g saturated fat, 1 g fiber, 9 g sugar. Exchanges: 2 carbohydrate, 1 fat. Carb choice: 2.