Pre-heat the oven to 350. Lightly mist 12 cups in a standard muffin/cupcake tin with cooking spray and set aside.

In a large mixing bowl, whisk together the eggs, egg whites, milk, vanilla extract, sugar and cinnamon until combined. Add the cubed bread pieces and stir together until the bread has soaked up the liquid in the bowl. Stir in the apple cubes. Spoon the mixture into the prepared muffin tin press down lightly on each to form them together.

In a small bowl, combine the butter, flour, brown sugar, pinch of cinnamon and pinch of salt. Use your hands to mash them all together into crumbs. Sprinkle these crumbs over top of the bread mixture in the muffin cups. Place the tin in the oven and bake for 25 minutes until the French toast muffins are cooked through and the tops are golden.