At Pastis in New York City, the chefs prepare a rich, open-faced croque-monsieur. Generously sauced with bechamel, it must be eaten with a fork and knife. For a Pastis-style sandwich that requires utensils to eat, use about 1/4 cup bechamel. If you prefer a sandwich that you can eat with your hands, brush on a thin layer of bechamel, slightly less than 1 Tbs. per sandwich.The perfect complement to this croque-monsieur is a simple salad of mixed baby greens dressed with a vinaigrette of extra-virgin olive oil, fresh lemon juice, salt and freshly ground pepper.