Brioche French Toast Casserole (with Cinnamon Toast Croutons)

1. For this recipe, you'll need to use 2 homemade brioche bread loaves. 1 cup of cubed brioche bread (1 inch cubes) is about 57 g / 2 oz. So, you'll need about 12 cups for the French toast layer, and about 4 cups for the cinnamon toast crouton layer.

Preparing the brioche bread

1. Cut the brioche bread into 0.75 - 1 inch thick slices. Then cut these slices into cubes, so that you have bread cubes that are roughly 0.75 - 1 inch in size.
2. If the bread loaves are already stale, then you can proceed with making the custard base. If you’re using fresh bread loaves, then use the oven to dry out the bread cubes as described below.

Drying out bread in the oven (only for fresh bread)

1. Place an oven rack on a half sheet pan. Preheat the oven to 250°F / 120°C (conventional).
2. Spread the bread cubes out on the oven rack. Alternatively, you can spread out the bread on a parchment paper-lined baking tray as well, but you will need to move the bread cubes around while baking so that they all dry out evenly.
3. Place the baking tray in the preheated oven. Bake the bread cubes for 15 - 20 minutes, or until the bread is feeling a little dry. Check on them to make sure the bread isn’t darkening.
4. Remove the bread from the oven and let it cool down to room temperature. Divide the bread and keep the portion for the topping separately (about a ¼ of the bread, or about 3 - 4 cups).

Making the custard base

1. Place all the ingredients for the custard in a large jug or blender jug.
2. Use a stick blender or regular blender to blend all the ingredients together. I prefer to add the lemon zest at the end, but you can add it with the rest of the ingredients too. I also don't always add the cinnamon and nutmeg, but you can add those in too.
3. If using a whisk to mix the custard, make a slurry with the cornstarch and just a few tablespoons of the milk / cream. Make sure that it's smooth and has no lumps.
4. Next, add the rest of the cream, milk, and other ingredients, and whisk vigorously until smooth. Whisking until smooth and lump free is important as the custard will absorb better if the custard mixture doesn’t seem gloopy (the egg white must be whisked or it'll create a gloopy flow).
5. Set it aside.

Preparing the French toast casserole

1. Prepare a 4 qt / 3.8 L casserole dish by brushing some butter all over the inside of the dish. You can also use a 9 x 13 in pan as well. Set it aside.
2. Spread the stale bread cubes for the French toast layer inside the casserole dish.
3. Evenly pour the custard mixture over the bread cubes. Let it sit for a few minutes, and then use a spatula to gently fold the bread cubes over. This is so that the bread on top is also able to completely absorb the egg mixture.
4. Using clean hands, gently press down on the bread cubes so that the custard is fully absorbed by the bread. These steps will ensure a perfectly creamy, custardy French toast layer throughout the casserole!
5. Cover the casserole dish and transfer it to the fridge. Let it refrigerate for at least 4 hours, or up to 24 hours to allow the bread to be saturated with the custard mixture.

Making the cinnamon toast croutons

1. Melt the butter, salt, and sugar until you have a smooth mixture. You can melt it together over the stove or in the microwave.
2. Mix well to ensure a smooth mixture, and the sugar is mostly dissolved. Add the cinnamon and mix it in well.
3. Add the remaining bread cubes into the butter sugar mixture and toss well until the butter and sugar coats all of the bread.
4. The croutons can be used right away, but the casserole must be ready to be baked as well. Until then, place the bread cubes in a container and this can be refrigerated until needed.

Baking the French toast casserole with cinnamon toast croutons

1. Preheat the oven to 350°F / 180°C.
2. Remove the casserole and sugar coated bread cubes from the fridge.
3. The cinnamon sugar croutons can be left whole, or broken into slightly smaller pieces if you prefer. Cover the whole surface of the casserole with the cinnamon croutons.
4. Bake in the preheated oven for 50 - 60 minutes, or until baked through. The time will vary and will be slightly different depending on if you use a metal baking dish, glass baking dish, or ceramic.
5. The French toast casserole is done when a thermometer inserted to the middle registers at around 160°F +.
6. If the croutons are caramelizing and burning too fast, tent a piece of foil on top to prevent this. I usually do this after the initial 25 - 30 minutes of baking.
7. Once baked through, remove from the oven and let the casserole sit for a few minutes until the cinnamon toast croutons harden and become nice and crispy. Serve while warm.
8. Serve with maple syrup or jam or whipped cream or creme fraiche.