Save to Pinterest My neighbor knocked on the door one Saturday morning holding a warm casserole dish wrapped in a tea towel. She'd just come back from Paris and wanted to share what she called her lazy Sunday version of a croque monsieur. The smell of nutmeg and melted Gruyère filled my kitchen before I even lifted the foil. I took one bite and understood why bistros never take this off the menu. It tasted like butter, comfort, and a little bit of showing off, all baked into one golden dish.
I made this for a brunch after my sister's baby shower, and it disappeared faster than the mimosas. Someone asked if I'd trained in France. I laughed and told them I just followed what my neighbor taught me, but honestly, the recipe does half the work. It sits in the fridge overnight, soaks up all the custard, and bakes into something that looks like you spent hours on it.
Ingredients
- White sandwich bread: Use soft, sturdy slices and cut the crusts off so the texture stays custardy, not chewy.
- Unsalted butter: Softened butter spreads easily on bread and adds richness without making the dish too salty.
- Gruyère cheese: This is the cheese that makes it taste French, nutty and melty with a slight sweetness that Swiss cheese can mimic if you need a swap.
- Whole milk and heavy cream: The custard base that soaks into the bread and turns it silky, not soggy.
- Large eggs: They bind the custard and give the casserole structure as it bakes.
- Cooked ham: Thinly sliced deli ham works perfectly, and you can skip it entirely if you want to keep things vegetarian.
- All-purpose flour: It thickens the béchamel and gives it that velvety, cling-to-the-spoon texture.
- Ground nutmeg: Just a pinch warms up the béchamel and makes the whole dish smell like a French kitchen.
- Salt and black pepper: Season every layer lightly so the flavors build without one bite tasting flat.
Instructions
- Get the oven ready:
- Preheat to 375°F and butter your baking dish generously so nothing sticks. This step sets you up for an easy cleanup later.
- Make the béchamel:
- Melt butter in a saucepan, whisk in flour, and cook it for a minute until it smells toasty. Slowly add the milk, whisking constantly, until it thickens into a smooth, pourable sauce, then season with nutmeg, salt, and pepper.
- Butter the bread:
- Spread softened butter on one side of each slice. This creates little pockets of richness and helps the top layer crisp up beautifully.
- Build the layers:
- Lay half the bread buttered side down in the dish, then add half the ham and cheese. Repeat with the remaining bread, ham, and cheese so every bite has balance.
- Pour the custard:
- Whisk together eggs, milk, cream, and a pinch of salt, then pour it evenly over the casserole. Press gently on the bread so it soaks up the liquid without floating.
- Add the béchamel:
- Pour the sauce over the top and spread it to the edges. It will bubble up and turn golden as it bakes.
- Bake until golden:
- Slide the dish into the oven and bake for 35 to 40 minutes until the top is puffed, golden, and bubbling at the edges. Let it rest for 10 minutes before slicing so the custard sets and doesn't run.
Save to Pinterest The first time I served this, my husband stood at the counter and ate two servings straight from the pan. He said it reminded him of the croque monsieur he had in Montmartre, except he didn't have to wait in line or pay twelve euros. I realized then that some dishes don't need a plane ticket to feel special.
Make It Your Own
If you want to skip the ham, sauté some mushrooms with thyme or wilt a handful of spinach and layer that in instead. I've also tucked in thin slices of tomato during summer when they're sweet and ripe. A tiny smear of Dijon mustard between the bread layers adds a sharp kick that makes the richness feel balanced instead of heavy.
Storing and Reheating
This casserole keeps covered in the fridge for up to three days and reheats beautifully in a low oven. I've even assembled it the night before, covered it tightly, and baked it fresh the next morning for brunch. The flavors deepen overnight, and you wake up to a dish that only needs 40 minutes in the oven before it's ready to impress.
Serving Suggestions
I like to serve this with a simple green salad dressed in lemon and olive oil to cut through the richness. A glass of chilled Chardonnay or even a light beer works if you're serving it for dinner.
- Add a handful of fresh herbs like chives or parsley on top right before serving for color and freshness.
- Serve it with cornichons or pickled onions on the side for a bright, tangy contrast.
- If you're feeding kids, cut it into squares and let them dip each bite into a little extra béchamel.
Save to Pinterest This casserole has become my go-to whenever I want something cozy that feels a little fancy. It's the kind of dish that makes people lean back in their chairs and sigh happily, and that's exactly what good food should do.
Recipe FAQs
- → Can I prepare this casserole ahead of time?
Yes, you can assemble the casserole up to 24 hours in advance. Cover tightly with plastic wrap and refrigerate. Add the béchamel sauce just before baking and allow an extra 5-10 minutes in the oven if baking directly from cold.
- → What type of bread works best for this dish?
White sandwich bread is traditional, but brioche or challah adds extra richness. Day-old bread works particularly well as it absorbs the custard mixture without becoming too soggy.
- → Can I substitute the Gruyère cheese?
Swiss cheese is the closest substitute and works beautifully. Emmental or Comté are also excellent choices. For a sharper flavor, try a mixture of Gruyère and sharp white cheddar.
- → How do I make this vegetarian?
Simply omit the ham and add sautéed mushrooms, caramelized onions, or fresh spinach between the layers. The béchamel and cheese provide plenty of rich, savory flavor on their own.
- → Why is my casserole too soggy?
This can happen if the bread is too fresh or if too much custard mixture is added. Use slightly stale bread and press gently after pouring the custard to ensure even absorption. Baking uncovered also helps achieve a golden, set top.
- → What should I serve alongside this casserole?
A crisp green salad with Dijon vinaigrette balances the richness perfectly. Roasted asparagus or a simple arugula salad with lemon also complement the dish beautifully.