Open-faced croque monsieur

• 4 store-bought crusty breadthick slices, about 2cm (3/4-inch)
• 30 g unsalted butter
• 30 g all-purpose flour
• 350 ml whole milk
• 200 g gruyère cheeseshredded
• 1 tbs dijon mustard
• ¼ tsp nutmegfreshly grated if possible
• 200 g deli hamabout 8 thin slices
• ½ tsp kosher salt
• ¼ tsp black pepperfreshly ground

1. 1

   Position an oven rack about 15cm (6 inches) from the broiler element and preheat the broiler to high. Arrange the 4 bread slices on the sheet pan.

2. 2

   Melt the butter in the saucepan over medium heat until it foams and smells nutty, about 1 minute. Add the flour and cook, stirring constantly with the whisk, until the mixture turns a shade darker and smells toasty, about 1 minute.

   Tip: Keep whisking so no lumps form — the roux should look like wet sand.

3. 3

   Slowly pour in the milk while whisking vigorously. Continue whisking until the sauce thickens enough to coat the back of a spoon and you can draw a clean line through it with your finger, about 3-4 minutes. Remove from heat.

4. 4

   Stir the dijon mustard, nutmeg, salt, black pepper, and about three-quarters of the shredded gruyère into the béchamel until the cheese melts into a smooth, glossy sauce. Taste and adjust salt if needed.

   Tip: Reserve the remaining gruyère for the topping — it'll give you that irresistible browned cheese crust.

5. 5

   Spread each bread slice with a thin layer of béchamel, then layer the ham on top, folding and overlapping to cover the bread. Spoon the remaining béchamel generously over the ham, letting it drip down the edges. Scatter the reserved gruyère over the top.

6. 6

   Broil until the cheese is deeply golden and bubbling with brown spots and the edges of the bread are toasted and crisp, about 3-5 minutes. Watch closely — broilers are unforgiving.

   Tip: Rotate the pan halfway through if your broiler has hot spots. Leftovers keep in the fridge for 1 day — reheat in a 180°C (350°F) oven for 5-6 minutes until warmed through and the cheese re-crisps. Best eaten fresh.

• saucepan (2-liter (2-quart))
• whisk
• sheet pan (half-sheet (18x13 inch))

Per serving

Nutritional values are estimates only.