Croque monsieur

For the béchamel, in a saucepan over a medium heat, melt the butter, add the flour and stir with a spatula to form a paste (known as a roux). Continue to stir and cook for 2-3 minutes. Remove the pan from the heat, pour in the milk and stir with a balloon whisk to blend well. Return the pan to the hob and increase the heat to high, whisking constantly. Once the sauce has thickened, reduce the heat and let it simmer gently for 1-2 minutes until it becomes a silky-smooth béchamel.

Remove the pan from the heat and stir in the mustard and 30g grated Cheddar. Season if needed; set aside (you can cool and chill at this point for up to 24 hours).

When ready to make the croques monsieurs, preheat the grill to medium-high and the oven to 200°C, gas mark 6. In a bowl, mix together the Comté and 150g Cheddar. Arrange the bread on a baking tray and toast 1 side under the grill (2-3 minutes).

Line the baking tray with baking parchment. Spread about 1 tbsp of béchamel sauce on the untoasted side of 2 slices of bread. Sprinkle ½ of the grated cheese mixture on top. On the other 2 slices, arrange the ham on the untoasted side, folding the slices as necessary to fit. Sandwich the bread slices together, toasted sides facing outwards. When you have made both sandwiches, spoon the rest of the béchamel over the top of each. Sprinkle with the remaining grated cheese and bake for 20-25 minutes, or until they are golden and cooked to your liking. Cut each sandwich in ½, sprinkle with the chives, if using, and serve.