Save to Pinterest My neighbor handed me a baking dish through the fence one Saturday morning, still warm and smelling like butter and cheese. She called it her lazy croque monsieur, and I called it genius. Instead of frying individual sandwiches, she'd turned the whole thing into a casserole that fed eight people with half the work. I made it the next weekend and haven't looked back since.
The first time I brought this to a potluck brunch, someone asked if I'd trained in Paris. I laughed because I'd been in my pajamas assembling it the night before while watching a cooking show. The béchamel does the heavy lifting here, turning simple ingredients into something that feels fancy but comes together with pantry staples. It's become my go-to whenever I want to impress without the stress.
Ingredients
- White sandwich bread: Removing the crusts isn't fussy, it's functional because they soak up the custard more evenly and the texture stays silky instead of chewy.
- Gruyère cheese: This is where the nutty, slightly sweet flavor comes from, and it melts into those beautiful golden strings that make everyone lean in closer.
- Cooked ham: Use good deli ham or leftover holiday ham, just avoid anything too salty or it'll overpower the creamy sauce.
- Whole milk and heavy cream: The combination creates a custard that's rich but not heavy, soaking into the bread without making it soggy.
- Béchamel ingredients: Butter, flour, milk, and nutmeg form the classic French white sauce that blankets everything in creamy, savory goodness.
- Eggs: They bind the custard and give the casserole structure so it slices cleanly instead of falling apart on the plate.
Instructions
- Preheat and prep your dish:
- Set your oven to 375°F and butter a 9x13-inch baking dish generously so nothing sticks. This step takes thirty seconds but saves you from scrubbing later.
- Make the béchamel sauce:
- Melt butter in a saucepan, whisk in flour, and cook for a minute until it smells toasty. Slowly pour in the milk while whisking constantly until it thickens into a smooth, velvety sauce, then season with nutmeg, salt, and pepper.
- Butter and layer the bread:
- Spread softened butter on one side of each slice, then arrange half the bread buttered side down in the dish. The butter creates little pockets of richness as it bakes.
- Add ham and cheese:
- Layer half the ham slices over the bread, then sprinkle half the Gruyère on top. Repeat with the remaining bread, ham, and cheese so every bite has balance.
- Whisk and pour the custard:
- Beat together eggs, milk, cream, and a pinch of salt, then pour it evenly over the layers, pressing gently so the bread soaks it up. Let it sit for a minute if you have time.
- Top with béchamel:
- Pour the warm béchamel over everything and spread it gently with a spatula. It'll look like a creamy blanket tucking the casserole in.
- Bake until golden:
- Slide it into the oven uncovered and bake for 35 to 40 minutes until it's puffed, bubbling, and golden brown on top. Let it rest for 10 minutes so it sets and doesn't spill everywhere when you cut into it.
Save to Pinterest My kids started requesting this for birthday dinners instead of cake, which tells you everything. There's something about the way the cheese stretches and the custard stays creamy that makes it feel like a hug on a plate. It's the kind of dish that turns a regular Tuesday into something worth gathering around the table for.
Make It Your Own
I've swapped the ham for turkey when I had leftovers, and once I left it out entirely and added sautéed mushrooms and spinach for a vegetarian version that my sister still talks about. A thin layer of Dijon mustard between the bread and ham adds a sharp little kick that cuts through the richness. You can also use brioche instead of sandwich bread if you're feeling indulgent, though it does get a bit sweeter.
Timing and Prep Ahead
This casserole loves to be assembled the night before and baked fresh in the morning, which makes it perfect for holiday brunches or when you have guests staying over. Just cover it tightly with foil and refrigerate, then let it sit at room temperature for 20 minutes before baking. The flavors meld overnight and the bread soaks up the custard more completely, so if anything, it tastes even better.
Serving and Pairing
I always serve this with a simple green salad dressed in lemon vinaigrette because the brightness cuts through the richness and makes the whole meal feel balanced. A crisp white wine like Chardonnay or even a light sparkling cider works beautifully alongside it. If you're serving it for brunch, add fresh fruit and coffee, and you've got a spread that looks like you planned it for weeks.
- Let it cool for at least 10 minutes before slicing or it'll be too soft to serve neatly.
- Leftovers reheat beautifully in a low oven covered with foil so they don't dry out.
- If the top browns too quickly, tent it loosely with foil for the last 10 minutes of baking.
Save to Pinterest This casserole has earned a permanent spot in my rotation because it's proof that comfort food doesn't have to be complicated. Make it once, and it'll become the dish people ask you to bring again and again.
Recipe Help Center
- → Can I make this casserole ahead of time?
Yes, assemble the casserole up to 24 hours in advance, cover tightly with plastic wrap, and refrigerate. Add the béchamel sauce just before baking and extend cooking time by 5-10 minutes if baking straight from the refrigerator.
- → What cheese works best besides Gruyère?
Swiss cheese is the closest substitute with a similar mild, nutty flavor. Emmental, Comté, or even a sharp white cheddar can also work well, though they'll alter the traditional French flavor profile slightly.
- → How do I prevent the bread from getting soggy?
Buttering both sides of the bread creates a barrier that helps prevent excessive sogginess. Also, don't let the casserole sit too long after pouring the egg mixture—bake it within 15-20 minutes of assembly for best texture.
- → Can I freeze leftover casserole?
Yes, cool completely, cut into portions, wrap tightly in plastic wrap and aluminum foil, and freeze for up to 2 months. Reheat individual portions in the oven at 350°F until warmed through, about 20-25 minutes.
- → What should I serve with this casserole?
A crisp green salad with Dijon vinaigrette balances the richness perfectly. Fresh fruit, roasted asparagus, or a simple arugula salad also pair beautifully. For beverages, consider white wine like Chardonnay or a light Pinot Noir.
- → How can I make this vegetarian?
Simply omit the ham and add sautéed mushrooms, caramelized onions, or wilted spinach between the bread layers. The béchamel and Gruyère provide plenty of savory depth on their own.