Making your French Toast Casserole is simple if you follow these steps:

1. Prepare the Bread: Cube the loaf of brioche or challah bread and place it in a greased 9×13-inch baking dish.
2. Whisk Eggs: In a large 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. Soak the Bread: Pour the egg mixture evenly over the cubed bread. Gently press down to ensure all bread pieces are soaked. Cover with plastic wrap.
5. Chill: Refrigerate for at least 1 hour or overnight for best results.
6. Preheat Oven: When ready to bake, preheat your oven to 350°F (175°C).
7. Bake: Remove the casserole from the refrigerator and uncover it. Bake for 45-50 minutes, or until the top is golden brown and a knife inserted in the center comes out clean.
8. Cool: Allow the casserole to cool for a few minutes before serving.
9. Serve: Cut into squares and serve warm with maple syrup, powdered sugar, and fresh berries if desired.

These steps make preparing the French Toast Casserole a breeze, allowing you to enjoy a hearty breakfast without the fuss.