A unique take on the croque-monsieur that will delight fans of melted cheese.
In a bowl, combine 4 tablespoons of butter with the Roquefort using a fork. Crush the walnuts with a mortar and pestle. Mix the Roquefort and butter with the crushed walnuts.
Butter one side of each slice of brioche. Place a half-slice of ham on the non-buttered side of the brioche. Spread the butter, walnut, and Roquefort mixture on the ham. Make a sandwich with another slice of brioche. Make sure the buttered side is on the outside of the sandwich.
Preheat the oven to 350 °F. Brown the croque-monsieur sandwiches in a hot skillet for 3 minutes on each side.
Place the croque-monsieur sandwiches directly on the oven grill and bake for 7 minutes until the bread turns golden-brown.
Serve with a frisée salad topped with walnut oil.