Ingredients:

  • 2 tbsp unsalted butter
  • 2 tbsp all-purpose flour
  • 1 cup whole milk, cold
  • 1.5 cups Gruyère cheese, freshly grated and divided
  • 1 pinch freshly grated nutmeg
  • 1 pinch salt and white pepper
  • 4 thick slices sourdough or brioche bread
  • 6 thin slices Jambon de Paris or high-quality smoked ham
  • 2 tsp Dijon mustard
  • 2 tbsp unsalted butter for searing
  • 2 large eggs
  • 1 tsp unsalted butter for frying
  • 1 pinch flaky sea salt and cracked black pepper

Instructions:

  1. Prepare the Roux: Melt 2 tbsp butter in a saucepan over medium heat. Whisk in 2 tbsp flour and cook for 2 minutes until it smells like toasted shortbread.
  2. Whisk the Béchamel: Slowly pour in the 1 cup of cold milk while whisking constantly. Simmer for 5 minutes until the sauce coats the back of a spoon.
  3. Season the Sauce: Stir in 1/2 cup of the Gruyère, a pinch of nutmeg, salt, and white pepper. Remove from heat once the cheese is melted and the aroma is rich and nutty.
  4. Prep the Bread: Spread 1 tsp of Dijon mustard on two slices of sourdough. Layer 3 slices of ham on each, then sprinkle with another 1/2 cup of cheese.
  5. Assemble Sandwiches: Top with the remaining bread slices. Press down gently to help them stick together.
  6. Sear the Sandwiches: Melt 2 tbsp butter in your skillet over medium high heat. Fry the sandwiches for 3 minutes per side until they are deep gold and crispy.
  7. Add the Topping: Move the sandwiches to a baking sheet. Generously spread the remaining Béchamel over the top of each and sprinkle with the last 1/2 cup of cheese.
  8. Broil to Bubbling: Place under the broiler for 3 to 5 minutes until the cheese is browned and the sauce is sizzling.
  9. Fry the Egg: While the sandwiches are broiling, melt 1 tsp butter in a non stick pan. Fry the eggs for 3 minutes until the whites are set but the yolks are still wobbly.
  10. Final Assembly: Slide one egg onto each sandwich. Garnish with flaky sea salt and cracked black pepper, then serve immediately.