Spray a small baking dish with 1 kcal spray.
Cut the slices of bread into cubes and place them in the baking dish.
In a bowl, mix the protein powder and cinnamon.
Using a fork, slowly add the milk and whisk until there are no lumps.
Whisk in the egg whites.
Pour the mixture over the cubes of bread.
Leave aside for about 30 minutes so the bread can absorb the liquid.
Add the sliced banana and spray well again with 1 kcal butter spray.
Bake in a preheated oven at 200 degrees Celsius for 20 minutes.
Serve hot from the oven or have it cold the next day. Really nice with a serving of Greek yogurt/Kvarg pot.