Croque Monsieur Sandwich

Ingredients

• 24 sliceswhite sandwich bread
• 24 slices, or about 720 ml (3 cups)sliced ham, or shredded ham
• 340 g (12 oz)grated Gruyère cheese
• 475 ml (2 cups)full-fat milk
• ½onion
• 5whole cloves
• A pinchnutmeg
• A pinchground white pepper
• 1bay leaf
• 1 sprigthyme
• 16 g (2 tbsp)plain flour
• 57 g (4 tbsp)unsalted butter
• A pinchsalt

Instructions

1. 1

   Heat the oven

   Preheat the oven to 200°C (400°F).

2. 2

   Prepare the onion

   Pierce the cloves into the half onion to make an onion piquet. Put it in a saucepan over low heat with the butter and let the onion soften gently in the butter for a few minutes.

3. 3

   Infuse the milk

   Add the milk, nutmeg, white pepper, bay leaf and thyme. Bring the mixture to a low simmer.

4. 4

   Thicken the sauce

   Once the milk simmers, remove and discard the onion and herbs. Add the flour and whisk quickly to prevent lumps, continuing until the sauce thickens and coats the back of a spoon.

5. 5

   Layer the bread

   Arrange half of the bread slices in a baking or roasting pan.

6. 6

   Assemble and bake

   Spread a thin layer of béchamel over the bread, add the ham and then the cheese, and spoon on more béchamel. Place the remaining bread slices on top and finish with a generous layer of cheese. Bake until the cheese has melted and turned golden.

What is a croque monsieur?

A croque monsieur is a French hot ham-and-cheese sandwich, typically enriched with béchamel and finished until bubbling and browned. This version turns the individual sandwiches into a sheet-pan bake, making it practical to serve a group.

The creamy sauce, savoury ham and nutty Gruyère give the filling its richness, while the top layer of cheese browns in the oven.

Nutrition and macros by portion

The nutrition label shows one serving as written: 390 calories, 25g protein, 34g carbs, 17g fat.

The bread supplies most of the carbohydrates, while the Gruyère, butter and full-fat milk contribute much of the fat; ham and cheese provide most of the protein. Balance a portion with salad or vegetables on the side.

Building the béchamel

Onion piquet: stud the onion with the cloves so they can infuse the milk without disappearing into the sauce. Remove the onion and whole aromatics before adding the flour.

Whisking: add the flour to the warm milk mixture while whisking briskly. Keep whisking until the sauce is smooth and thick enough to coat a spoon.

Choosing the filling

Ham: sliced ham gives distinct layers, while shredded ham can be spread across the bread for a more even filling. Either works with the sauce and cheese.

Gruyère: its savoury flavour suits the creamy béchamel and its grated form makes it easy to layer inside and scatter on top.

Assembling the sandwiches

Bottom layer: arrange half of the bread in the pan before spreading it with a thin coat of béchamel. This gives the filling a creamy base.

Top layer: add more béchamel over the cheese before closing the sandwiches, then finish with a generous covering of cheese. The recipe does not specify a baking duration, so use the melted, golden topping as your cue.

Serving from the pan

Let the pan sit briefly after baking so the melted filling settles before you portion the sandwiches. Serve warm, when the cheese is still soft.

A simple green salad or lightly dressed leaves make a fresh contrast to the rich sandwich. For brunch, fruit can also round out the plate.

Recipe notes & tips

• Grate the Gruyère evenly so it melts at a similar rate across the pan.
• Keep the milk at a low simmer rather than letting it boil vigorously.
• Whisk continuously as you add the flour to help keep the béchamel smooth.
• Spread the first layer of sauce thinly so the bread is coated without becoming soggy.
• Check the topping as it bakes and take the pan out when the cheese is melted and golden.

Variations

• Add mustard: spread a little Dijon mustard on the bread for a sharper flavour.
• Use another cheese: substitute Emmental for a similarly meltable, nutty finish.
• Add mushrooms: sauté them first, then layer them with the ham.
• Try wholemeal bread: use it in place of white sandwich bread for a heartier texture.
• Include a green side: serve with dressed leaves or steamed green vegetables.

Common mistakes to avoid

• Lumpy béchamel: whisk briskly as the flour goes in and keep whisking until smooth.
• Boiling the milk hard: keep it at a low simmer to infuse the aromatics gently.
• Leaving the aromatics in: remove the onion, cloves and herbs before thickening the sauce.
• Overloading the bread with sauce: use a thin layer inside so the sandwiches hold together.
• Baking by the clock alone: use melted, golden cheese as the doneness cue since no baking time is given.

How to store

Refrigerate leftovers in a covered container for up to 3 days. Reheat in an oven until hot throughout; the bread may soften after storage.

Frequently asked questions