Sautéed exotic mushrooms are smothered in truffle butter béchamel and two types of melty cheese in this twist on the classic bistro sandwich. Perfect for lunch or a light supper, serve with cornichons and dressed baby greens. Or top with a fried egg for an upgraded Croque Madame.
Check our post about Croque Monsieur for a little more on this beloved sandwich.
- 6 tablespoons Black Truffle Butter, divided use
- 1 pack Organic Chef’s Mix Mushrooms, trimmed and chopped
- 1 teaspoon fresh thyme leaves
- 1 tablespoon fresh chives, divided use
- Kosher salt & freshly ground black pepper
- ¼ cup all-purpose flour
- 1½ cups whole milk
- 1 tablespoon Dijon mustard
- Freshly grated nutmeg, to taste
- 8 slices Pain de Campagne
- 3 ounces Gruyere cheese, grated
- 3 ounces young Fontina cheese, grated
- Cornichons, for serving
- In a large skillet over medium-high heat, melt 2 tablespoons of black truffle butter. Add mushrooms and thyme, turn to coat; season with salt and pepper. Sauté until mushrooms have released their liquid and are deeply golden brown and slightly dry. Stir in half of the chives. Set aside.
- In a saucepan over medium-high heat, melt remaining 4 tablespoons of truffle butter. Add flour and whisk frequently until mixture turns golden brown and foamy, about 4 minutes. Gradually add milk, whisking constantly until smooth and thickened, about 4 more minutes. Remove from heat and whisk in mustard; season with nutmeg, salt, and pepper, to taste.
- Lay all eight slices of country bread on a sheet pan. Spread each slice with a thick coating of béchamel in an even layer. On four of the slices, top béchamel with the reserved mushroom mixture and half of the cheese. Lay the béchamel-only slices on top and spread the rest of the cheese over the béchamel. Sprinkle with the remaining chives.
- Bake until the cheese is melted and the tops of the sandwiches are golden brown and crusty, about 15-20 minutes. Serve immediately, with cornichons and baby greens dressed with vinaigrette.