Preheat oven to 350 degrees F. Prepare a baking dish (9X13) with cooking spray and set aside. Whisk together eggs, milk, half and half, sugar, brown sugar (first ½ cup) vanilla, and cinnamon in a large mixing bowl.
Cut bread into bite size pieces and add to bowl with egg mix. Gently mix together until all bread is coated (careful not to crumble bread). Once all bread has absorbed the egg then place it into your prepared baking dish.
For topping place all butter, flour, salt, brown sugar, and cinnamon in a small mixing bowl. Use a fork (or your hands) to mix together well until you form a crumble. Crumble this on top of your casserole.
Bake for 45-50 minutes until cooked through and a toothpick could come out clean.
Optional: serve topped with powdered sugar and syrup.
For this recipe, I used sourdough bread. Any thick or heavy bread will work great for this recipe. A simple sandwich bread will fall apart when mixing. For my topping, I used a few simple ingredients and mixed it until it felt like sand. I find pinching it with your fingers it the best way to mix. You must use cold butter for this recipe make sure to keep it in the fridge until you are ready to mix and top.
Make Ahead Instructions:
Refrigerate: Mix your casserole and top with crumble. Place plastic wrap over the casserole dish and keep in the fridge overnight. In the morning bake according to directions.Freezer: Follow the directions and bake your casserole in a freezer safe dish. Allow cooling then top your casserole dish with plastic wrap and foil making sure to have no open areas air could get in.Leave in the freezer for up to 3 months. When you are ready to serve to remove the casserole the night before and allow it to thaw in the fridge overnight. Bake at 350 for 15-20 minutes or until warm throughout.