1/2Teaspoonwater, more if needed to make a smooth glaze
Instructions
Place 2 Tablespoons of butter in a large coffee mug. Place the mug in the microwave and cook 30 - 45 seconds until the butter has melted. Add the remaining cake ingredients except the fresh blueberries to the mug. Mix thoroughly with a fork, stir in the blueberries.Place the mug into the microwave, cook 60 - 90 seconds until cake pulls away from the side of the mug and the top is dry. Combine the powdered sugar and water, stir until well incorporate, drizzle over cake.