croque mademoiselle


You’ve likely heard of croque monsieur, a grilled ham and cheese sandwich topped with béchamel sauce, and croque madame, the same sandwich with an egg on top. Croque mademoiselle is a lighter, more contemporary variation with a vegetable filling in lieu of—or in addition to—the traditional ham. I make mine sautéed zucchini and caramelized onions flavored with a bit of mustard and thyme. Instead of a heavy béchamel, the bread gets a light coating of cheese. I like to serve it topped with an egg, but you can go with just the sandwich on its own.





Makes 2 sandwiches


1½ tablespoons (22 ml) extra-virgin olive oil, or as needed
1 small onion, thinly sliced
Fine sea salt and freshly ground black pepper
½ medium zucchini, trimmed and sliced lengthwise into ⅓-inch (0.8 cm)-thick slices
4 slices Black Pepper Pain de Mie or other sandwich bread
2 teaspoons (5 g) wholegrain mustard
1½ teaspoons (1 g) finely chopped fresh thyme or 2 pinches of dried thyme
4 thin slices good-quality cured ham, such as jambon de Bayonne or prosciutto (optional)
2 tablespoons (1 ounce; 28 g) unsalted butter, melted
2 tablespoons (18 g) freshly grated Parmigiano-Reggiano
2 fried eggs (optional)


In a large skillet, heat the oil over medium-high heat. Add the onion and cook, stirring occasionally, until very soft and caramelized, 20 to 25 minutes. Season with salt and pepper. With a slotted spoon, transfer the onion to a plate; do not wipe out the pan.


Add the zucchini slices to the pan in a single layer (if there isn’t enough oil left from the onion, add a little more) and cook until golden on the first side, 3 to 4 minutes. Flip and cook the other side until golden and tender, 3 to 4 minutes more. Transfer the zucchini to the plate with the onion and set aside. Wipe out the skillet.


Spread one side of 2 slices of the bread with teaspoon of the mustard each and sprinkle with the thyme. Divide the onion evenly between the bread slices and top with the zucchini slices and 2 slices each of ham, if using. Finish with the remaining bread slices.


Heat the skillet over medium-low heat. Brush one side of each sandwich with some of the melted butter and place the sandwiches butter side down in the skillet. Cook, adjusting the heat as necessary, until golden on the first side, about 1 minute. Brush the unbuttered side with the remaining melted butter, flip the sandwiches, and top each with a tablespoon of the cheese; it should melt in the time it takes to brown the second side, about 2 minutes.


Top each sandwich with a fried egg, if you like, and serve hot.