It is hard to pick a favorite sandwich, but if I had to, the Croque Monsieur would always come out at the top of the list for me. I mean, what’s not to love? It’s basically a ham and cheese sandwich — which is already great — but then it’s topped with creamy béchamel (and maybe more cheese) and broiled until golden brown and bubbly. It’s incredible, and that’s precisely why I wanted to see how it would fare as a casserole. Perfect for brunch, this bake pairs crusty bread, a simple Dijon tinged custard, ham, and Gruyere for a twist on the traditional Croque Monsieur experience. (And don’t worry, I didn’t forget that bechamel!)

What Ingredients Are in Croque Monsieur Breakfast Casserole?

It’s actually pretty simple! You’ll need:

• A loaf of white bread. Something crusty and rustic works well.
• Eggs.
• Half and half.
• Dijon mustard.
• Sliced ham.
• Gruyere cheese. (My favorite!)
• Butter.
• Milk.
• Flour.
• A little pinch of nutmeg.

Those last four are for the béchamel.

How Do You Make Croque Monsieur Breakfast Casserole?

More or less, this is like a French toast bake, but savory. It follows the same method but has very different flavor. First up, you’ll want to dry out the bread a bit so it doesn’t turn to mush. Tear or cut it into 1-inch chunks, then spread it out on a baking sheet and pop it in the oven for just ten minutes or so. It doesn’t need to brown; you just want to remove some of the moisture.

Then, you’ll make the “custard.” Whisk together the eggs, half and half, and Dijon and pour it over the bread. You’ll want to let that soak for about ten minutes (which is why you need to dry it out a bit first!).

Once the bread has soaked up that goodness, you’ll pile half of it in a baking dish, top it with some ham and Gruyere, then top it with the other half of the bread, the rest of the ham and most of the gruyere and bake it until the cheese is melted and bubbly.

Towards the end of the baking time, you’ll work on what is arguably the most important part — the béchamel. Just melt the butter in a saucepan over medium heat and whisk in the flour. Keep whisking casually for a minute or so until you can smell that the raw flour has cooked out and it’s just starting to turn golden.

You might have heard that you need to gradually pour in milk for a smooth béchamel, but really that’s not true. As long as you keep whisking, you can pour all the liquid in at once. Whisk with enthusiasm for a minute or so, and then you can be a little lazier about it as you wait for the sauce to thicken up. Sprinkle a bit of nutmeg in there and then you can pour it all over the casserole.

The last step is to top it with a bit more Gruyere and broil it until it’s bubbly and golden, just like the delicious sandwich!