Yield: 8 servings / one 8x8x2″ container Serving size: 2/3 cup (150ml) 1 batch of keto sponge cake  OR 4-5 keto vanilla mug cakes 8 tablespoons (84g) powdered erythritol OR xylitol 4 large egg white (~120g) 4 large egg yolk (~80g) 1 cup (124ml) espresso 2 Tb. (30ml) rum OR other keto-friendly alcohol 1.5 cups (12oz / 340g) mascarpone OR cream cheese (optional) 1 tsp. vanilla (optional) 1/2 ts salt 1. Bake…