Croque Monsieur Toastie
A traditional croque monsieur is ham and gruyère with béchamel, baked or grilled with more sauce on top. In a sealed toastie maker the béchamel has to go inside, so it needs to be much thicker than usual or it will run straight out of the edges. This recipe uses a 2-minute microwave béchamel made with double the usual flour, chilled until it sets, so it spreads like soft butter and melts into a creamy layer in 4 minutes.
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Recipe: Croque monsieur toastie
Ingredients
- 4 slices medium-cut white bread (or soft white sourdough that fits your plates)
- 15g butter, for the béchamel
- 15g plain flour
- 100ml whole milk
- 1 small pinch ground nutmeg
- 1/2 tsp Dijon mustard
- 70g gruyère (or comté or emmental), finely grated, divided
- 4 thin slices cooked ham (about 70g total), patted dry
- 15g salted butter, softened, for the outside
Method
- Make the béchamel. Melt 15g butter in a microwave-safe jug for 20–30 seconds. Whisk in the flour until smooth, then whisk in the milk a little at a time.
- Microwave on full power in 30-second bursts, whisking after each one, for about 1.5–2 minutes in total, until it's very thick, like paste. Stir in the nutmeg, Dijon and 20g of the gruyère.
- Spread the béchamel on a plate and put it in the fridge for 5–10 minutes until it has set firm. Close the toastie maker and preheat it until the ready light comes on.
- Butter one side of all 4 slices. Put 2 slices buttered side down on the bottom plate.
- Spread a quarter of the cold béchamel on each bottom slice, in the centre only, keeping a 1.5cm border.
- Fold the ham so it fits inside the sealing line and lay it on top. Scatter the remaining 50g of gruyère over the ham, then spread the rest of the béchamel on the unbuttered side of the top slices.
- Put the top slices on, béchamel side down. Close the lid and cook for 4 minutes (5 in a deep fill).
- Optional French finish: put the toasties on a tray, scatter a little extra gruyère on top and put them under a hot grill for 1–2 minutes until the cheese bubbles. Rest for 1 minute before eating.
The béchamel shortcut, explained
A normal béchamel uses about 1 part flour to 10 parts milk and pours like double cream. Inside a sealed sandwich that runs straight to the edges. This one uses roughly 1:7. Once it's chilled, the starch sets into a firm gel that you can spread. In the toastie maker it softens back into a sauce, but by then the edges have sealed and it stays inside.
The microwave method also avoids the usual béchamel problems. Short bursts with a whisk in between stop lumps forming and stop it catching on the bottom, and there's no pan to wash. If it turns lumpy, push it through a sieve while it's warm.
Why gruyère?
Gruyère melts smoothly and has a nutty flavour, and with ham it's what makes a croque taste like a croque. Mature cheddar works as a British swap, but it's sharper and greasier. Emmental is milder and stretchier. There's more on melt behaviour in best cheese for toasties.
Is it still a croque monsieur?
Strictly, a croque has sauce and cheese on top as well as inside, browned under the grill. A sealed toastie maker can't do that, which is why we added the optional 2-minute grill finish. Our toastie vs grilled cheese guide explains how the croque, jaffle and toastie all differ.
Other appliances
A panini press or contact grill makes a flatter, crisper croque: 4–5 minutes on medium, with the béchamel kept well in from the edges. To make it fully in the oven, bake at 200°C for 8–10 minutes, then grill the sauce-topped croque for 2 minutes (see oven toastie). In a frying pan, cook on medium-low for 3 minutes per side, then finish under the grill.
Variations
- Croque madame: top the finished croque with a fried egg. It's a knife-and-fork job.
- Croque provençal: add 2 slices of deseeded, salted tomato (method in our cheese and tomato toastie).
- Croque champignon: fry 50g of sliced mushrooms until dry and cool them before adding. Also see the mushroom and gruyère toastie.
- Quick croque: no béchamel. Mix 1 tbsp of crème fraîche into the grated gruyère instead.
Mistakes to avoid
- Warm béchamel: it's runny and it will leak. Chill it until it's set.
- Béchamel near the edges: sauce in the seal stops the crimp setting. See how to stop toasties leaking.
- Too much ham: two thin slices per toastie is enough. Any more and the lid won't close in a standard machine.
- Grilling for too long: the edges burn fast once the toastie is already crisp. Two minutes at most.
The no-béchamel version is our ham and cheese toastie, and both are built on the classic cheese toastie. For machines that seal sauced fillings well, see best cheese toastie maker.
FAQs
Can I use shop-bought cheese sauce?
Most jarred or chilled cheese sauces are too runny for a sealed toastie. If you use one, reduce it in a pan until it's thick, then chill it until it sets before spreading.
Can I make the béchamel ahead?
Yes. Covered, it keeps in the fridge for up to 3 days, and cold béchamel is exactly what you want for this recipe.
What's the difference between a croque monsieur and a ham and cheese toastie?
The béchamel, the gruyère and traditionally a grilled cheese topping. A ham and cheese toastie is just bread, ham and cheese sealed in the machine.