Creating your Easy Overnight French Toast Casserole is straightforward. Follow these steps for the best results:

1. Prepare the Bread: Cut the challah or brioche into 1-inch cubes and place them in a large mixing bowl.
2. Mix Eggs: In another bowl, whisk together the eggs until well beaten.
3. Combine Wet Ingredients: Add the milk, heavy cream, granulated sugar, vanilla extract, cinnamon, nutmeg, and salt to the eggs. Whisk until fully combined.
4. Pour Mixture Over Bread: Pour the egg mixture evenly over the bread cubes, ensuring all pieces are coated.
5. Toss Gently: Use a spatula or your hands to gently toss the bread cubes, ensuring they absorb the liquid mixture.
6. Cover and Refrigerate: Cover the bowl with plastic wrap and refrigerate overnight. This allows the bread to soak up all the flavors.
7. Preheat Oven: In the morning, preheat your oven to 350°F (175°C).
8. Transfer to Baking Dish: Grease a 9×13-inch baking dish and transfer the soaked bread mixture to the dish, spreading it evenly.
9. Bake: Place the dish in the oven and bake for 40-45 minutes, or until the top is golden brown and a knife inserted in the center comes out clean.
10. Cool Slightly: Remove from the oven and let it cool for 5-10 minutes before serving.
11. Serve: Dust with powdered sugar, drizzle with maple syrup, and top with fresh berries if desired.

By following these easy steps, you will create a stunning and delicious Easy Overnight French Toast Casserole that your family and friends will rave about!