In a small bowl, mix Greek yogurt and 1 tbsp vanilla protein powder until smooth. Set aside.
In another bowl, combine all cake ingredients except strawberry, blueberries and food coloring. Divide the batter into two bowls.
In one bowl, add blueberries and a couple drops of blue food coloring and mix well. In the other bowl, add a couple drops of red food coloring and mix well.
Spray a microwave safe mug with non-stick cooking spray. Arrange the sliced strawberry at the bottom and cover with the red batter.
Spray a second mug with non-stick cooking spray and add blueberry batter. Place both mugs in the microwave and cook for about 2 minutes.
Plate the cakes and allow to cool for a minute. Add icing on top of one cake, then stack the other on top and ice the top cake. Top with sprinkles and more strawberries and blueberries, if desired.