Step 1:
Start by preparing your French bread or brioche. Slice it into thick, 1 to 1.5-inch slices. Arrange the bread slices in a single layer in your greased 9×13-inch baking dish. You can cut the slices into halves or quarters if necessary to fit the dish.

Step 2:
In a large mixing bowl, whisk together the eggs, heavy cream, whole milk, granulated sugar, vanilla extract, cinnamon, and a pinch of salt. Make sure everything is well combined.

Step 3:
Pour the custard mixture evenly over the bread slices in the baking dish. Use a spoon or ladle to gently press the bread down into the liquid to ensure each piece soaks up the custard. Cover the dish with plastic wrap and refrigerate overnight to allow the bread to soak up all the flavors.

Step 4:
The next morning, preheat your oven to 350°F (175°C). Remove the baking dish from the refrigerator and let it sit at room temperature for a few minutes.

Step 5:
Sprinkle brown sugar evenly over the top of the bread. This will create the signature crispy, caramelized crust. Bake for 40-45 minutes, or until the French toast is golden brown and the custard is set.