In a large mixing bowl, combine milk, Greek yogurt, egg whites, vanilla maple syrup and vanilla bean paste.
Stir in the oats, protein powder, baking powder, salt, cinnamon, nutmeg
Fold in the apples. Cover and chill overnight or at least 4 hours
Preheat oven to 350 degrees F.
Grease or line an 8 x 8 inch baking pan with parchment paper. Pour in the oat mixture. Bake at 350 degrees for 35-45 minutes until golden brown and set.
Make the icing while the oats bake. Combine cream cheese, milk, maple syrup and vanilla to a bowl and whisk until smooth. I used a hand held mixer for faster work and a smoother texture. Set aside until oats are baked.
Remove the baked oats from oven and let cool on a wire rack. Let cool 10-15 minutes.
Cover with icing. Cut into squares. Serve warm or wrap and save for later.
This recipe can be doubled for more servings.