Although I adore a classic croque monsieur, I do occasionally like to mix things up by incorporating various cheeses and adding other flavorings – I basically live life on the edge. This version with leeks feels cozy and seasonal, and a little luxurious, too. If I have friends coming over, I'll make the leek and bechamel base in advance, then fill the sandwiches just before cooking and serve them with a sharp green salad.
Leek and Comté Croques
Prep 10 minutes
Cook 40 min
Serves four
Two leeks (about 300g), cleaned and thinly cut
2 garlic cloves, peeled and finely sliced
60 grams of unsalted butter, with additional for spreading
Sea salt and black pepper
60 grams of all-purpose flour
300ml whole milk
One heaped teaspoon of English mustard
100g comté, grated finely
60g mature cheddar, grated finely
Eight slices of bread
Place the cut leeks, garlic and butter in a medium saucepan on a moderate-low flame, add seasoning generously, then cook, mixing now and then, for 15 to 20 minutes, until the leeks have softened and become caramelized.
At the same time, heat the oven to 240°C (220°C fan)/475°F/gas mark 9. Stir the flour into the leek mixture and cook for about a minute, until it becomes a biscuity roux. Pour in the milk, turn up the heat a little and whisk until the sauce is creamy. Continue mixing for a minute, until the sauce thickens, then remove from the stove. Whisk in the mustard and two-thirds of the grated comté and cheddar, and set aside.
Toast the bread (in rounds if necessary), then butter one side of each slice. Lay four slices of toast buttered side down on a parchment-covered tray. Coat each slice with a generous amount of the leek sauce, then cover with a second slice of toast, this time butter-side up. Finish each sandwich with a layer of the remaining leek bechamel, then top with the rest of the shredded cheese. Bake for 10 to 14 minutes, until the croques are browned, sizzling and melty.
Serve straight away, with a seasoned salad on the side, if you like.
