Lox Croque Monsieur Recipe

Make crème fraîche spread

In a small bowl, combine crème fraîche, lemon juice, lemon zest, salt, and black pepper. Stir until smooth and chill briefly while assembling sandwiches (about 5 minutes). This will add brightness and balance to the rich cheese and lox.

Prep other components

Grate Gruyère and set aside two portions: 1.5 cups for the interior and 1/2 cup for the topping. Drain capers and roughly chop if desired. Finely chop dill and chives.

Lay out 4 slices of bread (for 4 sandwiches open-faced). Spread about 1 teaspoon Dijon mustard over each slice, covering the surface lightly.

Evenly distribute the 1.5 cups grated Gruyère over the 4 mustarded slices (about 3–4 tablespoons per slice).

Top the grated Gruyère with thin slices of lox, dividing the 200 g evenly among the 4 sandwiches. Scatter capers and a sprinkle of chopped dill over the lox.

Place the remaining 4 slices of bread on top to make closed sandwiches. Lightly butter the outer faces of both top and bottom slices with the 3 tbs softened butter (reserve 1 tbsp for the pan).

Heat a large skillet or griddle over medium-low heat. Add the reserved 1 tablespoon butter and let it melt and coat the surface.

Place sandwiches in the skillet (work in batches if needed). Cook gently 3–4 minutes per side, pressing down lightly with a spatula, until bread is golden brown and interior cheese is beginning to melt. Reduce heat if bread is browning too quickly.

Transfer cooked sandwiches to a baking sheet lined with foil or parchment. Spoon the crème fraîche mixture (about 3/4 tablespoon per sandwich) thinly over the top slice of each sandwich, then sprinkle the remaining 1/2 cup grated Gruyère evenly on top.

Place the baking sheet under a broiler set 6–8 inches from the heat. Broil 1–2 minutes, watching closely, until the Gruyère is melted and lightly golden (avoid burning). Alternatively, place in a 425°F / 220°C oven for 3–5 minutes to melt and brown.

Remove from oven. Let sandwiches rest 1 minute. Optionally sprinkle with chopped chives and an extra pinch of dill. Slice each sandwich in half on the diagonal for easier hors d'oeuvres presentation.

Arrange on a platter and serve warm so the Gruyère is melty and the lox remains tender. Provide extra crème fraîche on the side if desired.