Combine all ingredients in a small bowl & whisk with a fork until smooth.
Combine all ingredients (minus Cream Cheese Icing) in a mug (or individual trifles) then whisk together with a fork until combine & nearly smooth. Microwave mixture on high power for 1 minute then check cake for doneness. If it is not fully cooked microwave for an additional 15 seconds. Serve warm topped with Cream Cheese Icing.