Prepare your pan to keep the cake from sticking, by lightly coating the inside with nonstick cooking spray or shortening and a dusting of flour.
Combine the cake mix, water, oil and egg whites in a large bowl until moistened. Beat with an electric mixer on medium speed for 2 minutes, until smooth.
Pour into the prepared pan.
Bake at 350F degrees for 40-45 minutes or until a toothpick instered into the center of the cake comes out clean.
Remove from the oven and place on a wire rack to cool for 10 to 15 minutes.
Invert the pan, releasing the cake onto a wire rack to cool completely. Place on a cake plate.
To make the lemon icing:
Place confectioner's sugar in a medium bowl or liquid measuring cup. Stir in the lemon juice a little at a time to achieve desired consistency. (The glaze should be thick, yet pourable.)