Recipe Overview
Chef Alexia Duchêne (of Le Chêne in New York City) presents an inspired take on France’s most decadent sandwich, drawing from versions served at Parisian bistros. This croque monsieur swaps the usual béchamel for a rich Comté cheese– and thyme-infused mornay sauce. Ooey-gooey raclette cheese adds a second layer of richness inside, alongside French ham and zingy Dijon mustard, all between slices of super soft pain de mie (a Pullman loaf or Japanese shokupan also work well). The sandwich is toasted under the broiler, allowing the sauce to char and melt into a velvety smooth shawl. Duchêne serves it with a simple salad of frisee, providing a bright and zippy foil.
Total Time: 45 minutes (plus cooling) | Yield: Makes 2 sandwiches
Note: You might find yourself with leftover sauce. Gently heat until fluid and serve on the side, or dip crust pieces of bread into it for an impromptu fondue treat.
Ingredients
- 1 cup plus 2 Tbsp. whole milk
- 3 sprigs thyme
- 6 Tbsp. unsalted butter, divided
- 5 Tbsp. (39 g) all-purpose flour
- 5 oz. Comté cheese, coarsely grated
- Freshly grated nutmeg
- Kosher salt
- 4 1"-thick slices pain de mie or other white sandwich bread, divided
- 2 Tbsp. Dijon mustard
- 4 oz. raclette cheese, thinly sliced into irregular ribbons with a vegetable peeler, divided
- 10 thin slices French or other ham
- 1 Tbsp. (or more) vegetable or other neutral oil
- Dressed greens (for serving; optional)
Step-by-Step Instructions
Prepare the Mornay Sauce
Step 1: Bring 1 cup plus 2 Tbsp. whole milk and 3 sprigs thyme to a simmer in a small saucepan over medium heat. Immediately reduce heat to low and keep warm.
Step 2: Melt 2 Tbsp. unsalted butter in another small saucepan over medium heat. Add 5 Tbsp. (39 g) all-purpose flour and cook, whisking constantly, until no pockets of dry flour remain, about 1 minute. Remove thyme from warm milk; discard. Gradually pour milk into roux, whisking constantly until combined. Bring to a simmer, then immediately remove pan from heat. Let béchamel sit until no longer hot but still warm.
Step 3: Add 5 oz. Comté cheese, coarsely grated, to béchamel and stir until melted and combined. Add freshly grated nutmeg to taste and season with kosher salt. Let mornay sauce cool, then cover with plastic wrap, pressing directly against the surface, and chill until ready to use.
Assemble the Sandwiches
Step 4: Spread one side of two 1"-thick slices pain de mie with 2 Tbsp. Dijon mustard, dividing evenly. Top with 2 oz. raclette cheese ribbons, dividing evenly. Divide 10 thin slices ham between bread slices. Top with the remaining 2 oz. raclette cheese ribbons, then close with the two remaining slices of bread.
Cook and Broil
Step 5: Heat 1 Tbsp. vegetable oil in a large skillet over medium. Place a sandwich in the pan and top with a grill press or heavy object. Add 1 Tbsp. unsalted butter, swirling to coat pan bottom. Cook until golden brown underneath, about 4 minutes. Remove press, turn sandwich, return press, add another 1 Tbsp. butter, and cook second side until golden, about 4 minutes. Continue cooking, removing weight and turning as needed to ensure even browning, until cheese is melted, 2–3 minutes more. Transfer to a rimmed baking sheet and repeat with the remaining sandwich and remaining 2 Tbsp. butter.
Step 6: Heat broiler to high (if using oven, place rack one slot down from top). Spread mornay sauce over sandwiches to make a ¼"-thick layer (you may not use all the sauce). Broil until sauce is deeply browned in spots, about 3 minutes (watch carefully to avoid burning).
Step 7: Transfer sandwiches to plates and mound dressed greens on the side if desired.
Make-Ahead and Serving
Do Ahead: The mornay sauce can be made 1 day ahead; keep chilled. Serve sandwiches hot, with extra warmed sauce on the side if desired. Explore Bon Appétit for more recipes, cooking advice, and restaurant recommendations.