Ingredients:
- 4 Tbsp Unsalted Butter (56 g), for the roux
- 4 Tbsp All-Purpose Flour (30 g)
- 2 cups Whole Milk, warmed (480 ml)
- 2 cups Gruyère Cheese, freshly grated (200 g), divided
- 1 tsp Dijon Mustard (5 ml)
- ¼ tsp Freshly Grated Nutmeg
- Fine Sea Salt, to taste
- Freshly Ground Black Pepper, to taste
- 8 slices Sourdough or Brioche Loaf (approx. 1.5 cm thick)
- 12 oz Quality Cooked Ham (340 g), thinly sliced
- 1 Tbsp Unsalted Butter, softened (15 g), for buttering bread
Instructions:
- Preheat the oven to 375°F (190°C). Grate all the cheese, ensuring the two 1-cup portions are kept separate. Prepare the bread, lightly buttering one side of each slice. This buttered side will face up during the final baking stage.
- Develop the Mornay Sauce: Melt the 4 Tbsp of butter in a saucepan over medium heat. Whisk in the flour until a smooth roux forms, cooking for 1–2 minutes. Gradually whisk in the warm milk, ensuring each addition is fully incorporated to prevent lumps. Bring to a gentle simmer and cook for 5–7 minutes until the sauce thickly coats the back of a spoon.
- Finish the Mornay: Remove the pan from the heat. Stir in the mustard, nutmeg, salt, and pepper. Fold in the first 1 cup (100g) of grated Gruyère cheese until the sauce is smooth and glossy. Taste and adjust seasoning.
- Assembly: Spread a thin layer of the Mornay sauce on the unbuttered side of all 8 bread slices. On 4 slices, layer a small sprinkle of cheese followed by generous layers of ham. Top the ham with the remaining 4 slices of bread, ensuring the buttery exterior side is facing up. Place the assembled sandwiches on a prepared baking sheet.
- The Baked Finish: Spoon a generous amount of the remaining Mornay sauce evenly over the tops of the four sandwiches, covering them completely. Sprinkle the remaining 1 cup (100g) of Gruyère cheese on top. Bake for 15 minutes, then switch the oven to high grill (broiler) and cook for 3–5 minutes until the topping is golden brown and caramelized. Rest for 2 minutes before serving cut diagonally.