Make-ahead French toast casserole with buttery bread and warm spices is the perfect family brunch dish for feeding a crowd. Assemble the night before for an effortless, impressive morning meal.
Cube the French bread into one-inch pieces and layer evenly in a greased 9x13 inch baking dish.
In a large bowl, whisk together eggs, whole milk, heavy cream, granulated sugar, vanilla extract, ground cinnamon, and salt until fully blended.
Pour the egg mixture evenly over the bread cubes, lightly pressing the bread so it absorbs the custard. Cover tightly and refrigerate overnight for best flavor and texture.
Remove the casserole from the fridge 30 minutes before baking. Preheat oven to 350°F. Dot the top with cold butter, scattering evenly.
Bake, uncovered, for 45–55 minutes until the casserole is puffed, golden brown, and a knife inserted in the center comes out clean. Let it rest 10 minutes before serving.