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.