Creating this delicious French Toast Casserole is straightforward when you follow these steps:

1. Prepare the Bread: Start by cutting your bread into 1-inch cubes. If the bread is fresh, allow it to sit out for a few hours to stale slightly for better absorption.
2. Grease the Pan: Lightly grease a 9×13-inch baking dish with butter or cooking spray.
3. Add the Bread: Place the cubed bread in an even layer in the greased baking dish.
4. Make the Custard: In a large mixing bowl, whisk together the eggs, milk, heavy cream, sugar, vanilla extract, cinnamon, nutmeg, and salt until well combined.
5. Combine: Pour the custard mixture over the cubed bread, making sure to soak all pieces well. If desired, gently press down on the bread with a spatula to ensure absorption.
6. Chill: Cover the dish with plastic wrap and refrigerate for at least 2 hours, or overnight for best results. This step allows the bread to fully absorb the custard.
7. Preheat Oven: When ready to bake, preheat your oven to 350°F (175°C).
8. Bake: Remove the plastic wrap and pour the melted butter evenly over the top of the casserole. Bake for 45-50 minutes until the top is golden and a knife inserted in the center comes out clean.
9. Cool Slightly: Let the casserole cool for about 10 minutes before serving to allow it to set further.
10. Serve: Slice into squares and serve warm, drizzled with maple syrup and a dusting of powdered sugar, if desired. Garnish with fresh berries for an added touch.