Step 1: Prepare Your Baking Dish. Lightly grease a 9x13 inch baking dish with butter or non-stick cooking spray. This prevents sticking and makes serving your french toast recipe casserole much easier.
Step 2: Cut the Bread. Slice your day-old bread into 1 to 1.5-inch cubes or thick slices. Evenly distribute the bread cubes into your prepared baking dish. Don't pack them too tightly; you want space for the custard to seep in. This is a crucial step for a fluffy french toast recipe casserole.
Step 3: Whisk the Custard. In a large bowl, whisk together the eggs, milk (or cream), granulated sugar, brown sugar, vanilla extract, cinnamon, and nutmeg until well combined and smooth. Make sure there are no streaks of egg white remaining. This custardy mixture is the heart of your french toast recipe casserole.
Step 4: Pour Over Bread. Carefully pour the egg mixture evenly over the bread cubes in the baking dish. Gently press down on the bread with a spatula to ensure all pieces are submerged and fully absorb the liquid. This ensures every bite of your french toast recipe casserole is moist and flavorful.
Step 5: Prepare the Streusel Topping (Optional but Recommended). In a separate small bowl, combine the melted butter, brown sugar, flour, and a pinch of cinnamon. Use a fork or your fingertips to mix until crumbly. Sprinkle this mixture evenly over the top of the bread and custard. This streusel adds an incredible crunch to your french toast recipe casserole.
Step 6: Chill Overnight. Cover the baking dish tightly with plastic wrap and refrigerate for at least 4 hours, or ideally, overnight (8-12 hours). This allows the bread to fully soak up the custard, resulting in an incredibly moist and flavorful french toast recipe casserole. For easy storage, especially if you're making this ahead for guests, consider using reliable Basics Glass Food Storage containers for any leftover ingredients or for prepping other components of your meal.
Step 7: Preheat and Bake. The next morning, remove the casserole from the refrigerator about 30 minutes before baking to bring it closer to room temperature. Preheat your oven to 375°F (190°C). Remove the plastic wrap and bake for 40-50 minutes, or until the top is golden brown and the center is set. A knife inserted into the center should come out clean. If the top starts browning too quickly, you can loosely tent it with aluminum foil.
Step 8: Serve Warm. Let the french toast recipe casserole cool for 5-10 minutes before serving. This allows it to set up a bit more. Serve warm with your favorite toppings like maple syrup, fresh berries, powdered sugar, or whipped cream. Enjoy your perfect french toast recipe casserole!