Croque Monsieur with Mornay Sauce

Croque Monsieur with Mornay Sauce

Prep Time


Cook Time



Croque Monsieur with Mornay Sauce

Recipe Courtesy of

A traditional French croque monsieur sandwich is usually dipped into eggs then grilled on a sandwich-grilling iron.

Nutrition Facts

4 sandwiches

Facts per Serving

Calories: 1156 Fat, Total: 78g Carbohydrates, Total: 49g
Cholesterol: 316mg Sodium: 2231mg Protein: 68g
Fiber: 4g % Cal. from Fat: 61% % Cal. from Carbs: 17%

Product Recommendation

DeLonghi Retro Collection Panini Grill, Black & Stainless Steel


  • FOR THE MORNAY SAUCE: 2 tablespoons butter
  • 1/4 cup finely chopped onion
  • Pinch of kosher salt
  • 1 bay leaf
  • 2 tablespoons all-purpose flour
  • 2 cups whole milk
  • 1/2 cup finely grated Gruyere cheese
  • 1/4 cup finely grated Parmigiano-Reggiano
  • 1 large egg yolk
  • FOR THE SANDWICHES: 6 tablespoons unsalted butter
  • 8 slices fresh country-style white bread
  • 1 pound Gruyere cheese, sliced 1/16 inch thick (about 24 slices)
  • 12 ounces thinly sliced ham (about 16 slices)


  • 1 FOR THE SAUCE: Melt butter in heavy medium saucepan over medium heat.
  • 2 Add onion and pinch of salt. Saute until onion is tender and translucent, about 5 minutes. Add flour and stir 3 minutes (do not brown).
  • 3 Gradually whisk in milk. Add bay leaf. Simmer until sauce thickens, stirring occasionally, about 5 minutes. Season with salt and pepper. Cool to lukewarm, about 30 minutes.
  • 4 Gradually add cheese and stir until completely melted. Remove Mornay sauce from heat.
  • 5 Lightly beat egg yolk in small bowl. Whisk 1 tablespoon of Mornay sauce into egg. Fold egg mixture into Mornay sauce. Cover to keep sauce warm.
  • 6 FOR THE SANDWICHES: Spread 1/2 tablespoon butter over one side of each bread slice.
  • 7 Place 4 bread slices on work surface, buttered side down. Divide half of cheese among bread slices. Place ham slices atop cheese, dividing evenly. Top with remaining cheese. Top sandwiches with remaining 4 bread slices, buttered side up.
  • 8 Heat griddle or cast iron skillet over medium heat. If using a griddle, cook sandwiches until bottom is golden brown and cheese is melted, about 3 minutes per side. If using a cast iron skillet, cook sandwiches until golden brown, about 3 minutes.
  • 9 Turn sandwiches over, then place skillet in 400ºF oven, until golden brown on bottom and cheese is melted, about 5 minutes.
  • 10 Place sandwiches on a heatproof plate or baking sheet. Spoon 1/4 cup sauce over each sandwich. Broil until sauce is pale golden and bubbles, about 2 minutes. Serve immediately.


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