1. Whisk all ingredients (except berries) together in a bowl, adding the milk little by little until mixture resembles pancake batter.
2. Pour mixture into a microwave-safe mug or bowl. Cook on full power for 2 minutes. (Cooking times may vary.) Be careful that the mug isn’t too hot when removing from microwave.
3. Serve with a topping such as hot stewed berries, if desired: To make, put 1 cup berries into microwave and cook until thick and sticky. Pour over cake.