For cakes, spray insides of 2 large microwave-safe mugs with cooking spray. Whisk together Reddi-wip, Egg Beaters, cake mix and cinnamon 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 syrup, combine lime peel, lime juice, water, sugar and rum extract in small microwave-safe bowl. Microwave on HIGH 30 seconds or until sugar is dissolved when stirred.
Poke holes in cakes with fork; pour half of syrup over cakes. Let stand 1 minute. Invert each cake onto a plate; pour remaining syrup over cakes. Serve with additional Reddi-wip, if desired.