Croque-monsieur: simple buttered ham-and-cheese bistro sandwich
Croque-monsieur is a hot French bistro sandwich of pain de mie, ham and melting cheese. This preparation deliberately uses the simple buttered form: there is no fried egg, no mustard and no béchamel. That keeps the sandwich recognisably different from the croque-madame rather than treating the two names as interchangeable plates with optional toppings.
Because the ingredient list is short, balance depends on allocation and heat. Each sandwich contains two 40 g bread slices, 40 g cooked ham and 40 g cheese. Butter is spread thinly over the outside faces, then the sandwiches are toasted over medium-low heat until crisp and golden. That slower pan heat builds colour without scorching before the centre has warmed.
A five-minute oven finish at 180 °C solves the remaining timing problem: the cheese can melt through without making the bread much darker. Serve as soon as the centre is uniformly hot and the cheese is fluid. This is a sandwich whose quality falls quickly if it waits, because steam migrates from the hot filling into the bread.
