Croque Monsieur Recipe

Prep bread

Lay out 8 slices of bread. Spread roughly 1/2 teaspoon Dijon mustard on the interior of each slice that will hold fillings (approximately 2 tsp total spread across 4 sandwiches).

Lightly butter the exterior sides of each bread slice (about 1/2 tbs per slice) for grilling. Set aside.

If using ham

Arrange 2 slices of cooked ham on each of 4 mustard-spread bread slices. Top ham with about 1/4 cup grated or thinly sliced Emmental (2 cups total divided among sandwiches).

If using mushrooms (vegetarian option)

Heat 1 tbs olive oil in a skillet over medium-high heat. Add sliced mushrooms and a pinch of salt; sauté until they release liquid and it evaporates and mushrooms are browned, about 6–8 minutes. Add minced garlic and thyme in the last minute, stir, then season with 1/4 tsp additional salt and 1/4 tsp black pepper. Remove from heat. Divide mushrooms evenly among 4 mustard-spread bread slices and top with the same amount of Emmental as above (about 1/2 cup per two sandwiches equivalent; total 2 cups divided).

Top each prepared slice with the remaining plain bread slices, buttered side out, to form 4 sandwiches.

In a small saucepan, melt 3 tbs unsalted butter over medium heat. When bubbling (but not browned), whisk in 3 tbs flour and cook, whisking constantly, for 1–2 minutes to form a blond roux.

Gradually whisk in 2 cups warm whole milk a little at a time to avoid lumps. Bring to a gentle simmer, whisking constantly, until the sauce thickens to a smooth, coat-the-back-of-a-spoon consistency, about 4–6 minutes.

Remove from heat and whisk in 1/4 tsp grated nutmeg, 1/2 tsp salt, and 1/4 tsp white or black pepper. If using, stir in 1/2 cup grated Gruyère or extra Emmental for a richer béchamel. Taste and adjust seasoning.

Reserve about 1/3 cup of béchamel for the salad dressing (optional) and keep the remainder warm.

Preheat oven broiler (or a heavy skillet/griddle) to medium-high (or broil setting). If using skillet: heat over medium and add a small knob of butter or a little oil.

Place sandwiches in skillet or on a baking sheet (buttered sides down). Cook 3–4 minutes per side in the skillet until bread is golden and cheese inside is melting. If using broiler: place sandwiches on a baking sheet and broil 2–3 minutes until the top is golden, flip and broil another 1–2 minutes to crisp the bottom.

Transfer sandwiches to an ovenproof dish or keep on baking sheet. Spoon generous béchamel over the top of each sandwich (about 3–4 tbs per sandwich). Sprinkle additional grated Emmental or Gruyère (about 1 tbs) on top of the béchamel.

Place under the broiler for 2–4 minutes until the béchamel is bubbly and the cheese topping is golden brown. Watch closely to avoid burning.

Remove from oven and let rest 1–2 minutes before serving.

While sandwiches finish under the broiler, make the simple dressing by whisking together 2 tbs olive oil, 1 tbs lemon juice or vinegar, 1/2 tsp Dijon mustard, 1/2 tsp honey (optional), salt and pepper to taste (about 1/4 tsp salt and 1/4 tsp pepper). If you reserved 1/3 cup béchamel, whisk 1–2 tbs into the dressing for a creamier texture.

Toss 4 cups mixed salad greens with the dressing just before serving.

Place each Croque Monsieur on a plate with a portion of dressed salad on the side. Optionally garnish with a small sprinkle of fresh thyme or chopped chives. Serve immediately while hot.