Croque Monsieur Recipe

Meet your new favorite Croque Monsieur—my husband calls it “insanely good!!!” I’ve perfected every detail of this recipe to bring you the ultimate version: think velvety béchamel, triple cheese magic, and buttery, golden sourdough with just the right crunch. See the post for lots of expert tips and variations!

📝 Ingredients

• 1 1/2 cups milk
• 4 tablespoons unsalted butter
• 1/4 cup flour
• 1/4 teaspoon salt
• 1/8 tsp EACH ground nutmeg, white pepper
• Pinch of cayenne ((not traditional, optional – YUM!))
• 8 1/2-inch thick slices country-style sourdough bread or pan de mie
• 6 oz. Gruyere cheese, (thinly sliced)
• 6 oz. ham slices, (preferably black forest )
• 2 tablespoons Dijon mustard
• 4 tablespoons unsalted butter, (divided)
• 2 tablespoons olive oil, (divided)
• 3 oz. (3/4 cup) gruyere cheese, (shredded)
• 1/4 cup Parmesan (grated on microplane grater)

👨‍🍳 Instructions

1. 1Prep: Preheat the oven to 400°F. Line a large baking sheet (21x15) with parchment paper.
2. 2Make roux: Melt four tablespoons of unsalted butter in a medium to large saucepan over medium heat. Reduce the heat to low, then add flour. Cook while whisking constantly for 2 minutes.
3. 3Add milk: Remove from the heat. While whisking constantly, add about a quarter of the milk and whisk until smooth (it will be thick). Continue to whisk while adding the milk a couple of tablespoons at a time, whisking until smooth between each addition. Add the salt, nutmeg, white pepper, and cayenne.
4. 4Thicken: Bring to a simmer and continue to whisk for a few minutes until thickened to the consistency of spreadable butter or pudding, not runny at all. Remove from the heat.
5. 5Slather Béchamel: Add 8 slices of bread to the prepared baking sheet. Spread half of the béchamel thickly over ALL the slices (like you would butter toast- it will be thick).
6. 6Assemble: Top FOUR pieces of the béchamel bread with half of the Gruyere slices, followed by all of the ham (folding as needed to fit). Spread a thick layer of Dijon over the ham, then top with the remaining slices of Gruyere. Close the sandwiches with the remaining slices of bread, béchamel side down.
7. 7Pan fry: Heat one tablespoon olive oil in a cast-iron skillet over medium heat. Once hot, add the butter to melt. Working in batches, grill the sandwiches for about 2 minutes per side, until deeply golden brown, pressing down occasionally with a spatula so they grill evenly (the cheese will not be completely melted). Transfer back to the parchment paper-lined baking sheet.
8. 8Topping: Spread the remaining béchamel on the top slices of each sandwich. (Gently reheat and re-whisk the béchamel with a splash of milk if it's become too cold/thick to spread.) Add the shredded Gruyere and grated Parmesan over the béchamel.
9. 9Bake: Bake for 10-12 minutes, until the cheese is melted, then broil for 2-3 minutes until the top is golden.
10. 10Serve immediately with a fork and knife to enjoy every gooey bite (its rich, cheesy goodness is too messy and hot to eat with hands).