For cakes, spray insides of 2 large microwave-safe mugs with cooking spray. Whisk together Reddi-Wip, Egg Beaters, and cake mix in medium bowl. Place half of batter in each mug. Microwave each mug individually on high 1 minute to 1 minute 15 seconds or until set.
For frosting, stir together cream cheese spread, 2 servings Reddi-Wip, and sugar in small bowl until blended. Invert each cake onto a plate; top each with half of the frosting.