Skinny Eggnog Cake

Bahan-bahan (15 porsi)

• 16.5 oz package yellow cake mix
• 6 - oz fat-free Greek yogurt
• 1 cup water
• 2 large egg whites
• 1 1/2 tsp ground nutmeg (plus more for garnish)
• baking spray
• 10 oz Truwhip or reduced fat whipped topping
• 1 tbsp rum (or a few drops rum extract)