Croque Monsieur Gruyere Ham

Set oven temperature to 200°C and allow to preheat thoroughly.

Melt butter in a medium saucepan over medium heat. Add flour and stir continuously until mixture turns golden and emits a fragrant aroma, about 4–5 minutes. Add bay leaves and gradually pour in whole milk, whisking constantly until smooth. Simmer, whisking occasionally, for approximately 5 minutes or until thickened to a sauce consistency. Remove from heat and whisk in both mustards, freshly grated nutmeg, and kosher salt. Discard bay leaves before using.

Arrange bread slices on a work surface. Evenly spread one side of each slice with béchamel sauce. Top four slices with half of the grated Gruyère and distribute sliced ham evenly atop cheese. Cover each with the remaining bread slices, béchamel side up. Sprinkle remaining Gruyère and herbes de Provence over the top.

Transfer assembled sandwiches to a parchment-lined baking tray. Bake for approximately 15 minutes, or until cheese is bubbling and golden. Shift tray under the broiler set to low, broiling for an additional minute to achieve a deep golden crust.

Let sandwiches cool for several minutes. Slice each in half and serve warm.