Ingredients:

  • 2 tablespoons (30 ml) unsalted butter
  • 2 tablespoons (15g) all-purpose flour
  • 1 1/2 cups (355 ml) whole milk
  • 1/4 teaspoon freshly grated nutmeg
  • Salt and freshly ground black pepper to taste
  • 4 slices good-quality white bread (such as pain de mie or brioche)
  • 4 tablespoons Dijon mustard
  • 4 slices Gruyère cheese (about 4 ounces / 113g total)
  • 4 slices cooked ham (about 4 ounces / 113g total)
  • 2 tablespoons unsalted butter, softened (for spreading)
  • 2 large eggs (Optional for Croque Madame)
  • Grated Parmesan cheese for topping (Optional)

Instructions:

  1. Prepare the Béchamel Sauce: Melt butter in the saucepan. Whisk in flour and cook for 1-2 minutes (roux). Gradually whisk in milk until smooth. Add nutmeg, salt, and pepper. Simmer, stirring constantly, until thickened (about 5-7 minutes).
  2. Assemble the Sandwiches: Spread Dijon mustard evenly on all bread slices. Layer 2 slices of Gruyère, then 2 slices of ham, and top with another 2 slices of Gruyère on two of the bread slices. Top with the remaining bread slices.
  3. Spread and Bake (or Pan-Fry): Spread softened butter on the outside of both sandwiches. Baking Method: Place sandwiches on a baking sheet and bake at 375°F (190°C) for 8-10 minutes per side, or until golden brown and cheese is melted and bubbly. Pan-Fry Method: Cook in a skillet over medium heat for 4-5 minutes per side, or until golden brown and cheese is melted and bubbly.
  4. Top with Béchamel and Broil (or finish in Pan): Spread a generous layer of béchamel sauce over the top of each sandwich. Sprinkle with Parmesan cheese (optional). Baking Method: Broil for 1-2 minutes, or until the béchamel is bubbly and lightly browned. Watch carefully to avoid burning! Pan-Fry Method: Continue to cook in the pan, covered, until the béchamel is heated through and lightly browned.
  5. (Optional) Make it a Madame: While the sandwiches are baking/pan-frying, fry the eggs to your liking. Top each sandwich with a fried egg immediately before serving.