Mushroom Croque-Monsieur

A luxurious French sandwich featuring ham, Gruyère cheese, and a savory mushroom mixture, all topped with a creamy béchamel sauce. This elevated version of the classic croque-monsieur combines earthy mushrooms with melted cheese and crispy bread.

6 servings

40 min

Published October 4, 2025

Ingredients

•1½ tablespoons butter
•1½ tablespoons all purpose flour
•1½ cups whole milk
•1 piece bay leaf
•½ cup finely grated Parmesan cheese
•1 pinch freshly grated nutmeg
•1 dash Hot pepper sauce
•8 ounces crimini mushrooms
•7 tablespoons butter
•2 tablespoons minced shallot
•12 slices egg bread
•6 slices ham
•12 ounces Gruyère cheese
•2 tablespoons grated Parmesan cheese
•1 garnish Fresh tarragon leaves

Cooking Instructions

1.
Melt butter in heavy-medium saucepan over medium heat. Add flour; stir until pale golden, about 2 minutes. Whisk in milk. Add bay leaf. Increase heat to medium-high; whisk until mixture begins to boil. Reduce heat to medium; stir until sauce coats back of spoon, about 5 minutes. Remove from heat. Add cheese and nutmeg. Season with hot sauce, salt, and pepper.
10 min
2.
Place mushrooms in processor. Using on/off turns, process until finely chopped. Melt 3 tablespoons butter in large skillet over medium-high heat. Add mushrooms and shallot; stir until mushrooms are browned and dry, about 8 minutes. Transfer to plate to cool.
12 min
3.
Preheat broiler. Spread remaining butter over 1 side of bread slices. Place bread, buttered side up, on rimmed baking sheet. Broil until golden, watching closely and rotating sheet halfway through broiling, about 3 minutes. Cool bread. Preheat oven to 450°F. Turn 6 bread slices over; top with ham and sliced cheese. Top with remaining bread slices, broiled side up. Press to compress. Spread about 2 tablespoons sauce over sandwiches, leaving 1/3-inch plain border. Divide mushroom mixture atop sauce. Sprinkle with grated Gruyère and Parmesan.
8 min
4.
Bake sandwiches until cheese inside melts and cheese on top turns golden, about 10 minutes. Top with tarragon, if desired.
10 min

Ingredients

•1½ tablespoons butter

•1½ tablespoons all purpose flour

•1½ cups whole milk

•1 piece bay leaf

•½ cup finely grated Parmesan cheese

•1 pinch freshly grated nutmeg

•1 dash Hot pepper sauce

•8 ounces crimini mushrooms

•7 tablespoons butter

•2 tablespoons minced shallot

•12 slices egg bread

•6 slices ham

•12 ounces Gruyère cheese

•2 tablespoons grated Parmesan cheese

•1 garnish Fresh tarragon leaves

Cooking Instructions

Melt butter in heavy-medium saucepan over medium heat. Add flour; stir until pale golden, about 2 minutes. Whisk in milk. Add bay leaf. Increase heat to medium-high; whisk until mixture begins to boil. Reduce heat to medium; stir until sauce coats back of spoon, about 5 minutes. Remove from heat. Add cheese and nutmeg. Season with hot sauce, salt, and pepper.

10 min

Place mushrooms in processor. Using on/off turns, process until finely chopped. Melt 3 tablespoons butter in large skillet over medium-high heat. Add mushrooms and shallot; stir until mushrooms are browned and dry, about 8 minutes. Transfer to plate to cool.

12 min

Preheat broiler. Spread remaining butter over 1 side of bread slices. Place bread, buttered side up, on rimmed baking sheet. Broil until golden, watching closely and rotating sheet halfway through broiling, about 3 minutes. Cool bread. Preheat oven to 450°F. Turn 6 bread slices over; top with ham and sliced cheese. Top with remaining bread slices, broiled side up. Press to compress. Spread about 2 tablespoons sauce over sandwiches, leaving 1/3-inch plain border. Divide mushroom mixture atop sauce. Sprinkle with grated Gruyère and Parmesan.

8 min

Bake sandwiches until cheese inside melts and cheese on top turns golden, about 10 minutes. Top with tarragon, if desired.

10 min