Place all ingredients into a large microwave-safe mug and mix vigorously with a spoon to form a smooth batter. Microwave on high for 1 minute and 30 seconds. Check the cake after 1 minute and adjust the overall cooking time according to your microwave oven. Don’t overbake. Let cool until warm and serve.
* Percent Daily Values are based on a 2,000 calorie diet. Your daily value may be higher or lower depending on your calorie needs.
VARIATION: It’s easy to vary this one-mug wonder. For peanut butter and chocolate chip cake, add 2 tablespoons (22 g) dark chocolate chips or chopped homemade sugar-free chocolate to the batter and mix well. For a peanut-butter-and-jelly cake, drop 1 tablespoon (15 g) Easy Sugar-Free Strawberry Jam into the batter before baking. Use a fork to create a swirl in the batter, then bake.