In France, these toasted cheese and ham sandwiches are very popular.
The Illustrated Kitchen Bible: 1,000 Family Recipes from Around the World
| 14 oz (400 g) Gruyere cheese, grated | 2 tsp Dijon mustard | |
| 4 tbsp butter, plus softened butter for spreading | 8 slices white sandwich bread | |
| 2 tbsp all-purpose flour | 8 thin slices ham | |
| 2/3 cup whole milk |
Cut 4oz (115g) of the cheese into thin slices and shred the rest.
Melt the butter in a medium saucepan over low heat. Whisk in the flour and let bubble without browning for 1 minute. Whisk in the milk. Simmer, whisking often, until smooth and thick. Add the shredded cheese and mustard and stir until the cheese is melted.
Position a broiler rack 6 inches (15 cm) from the heat and preheat the broiler. Toast the bread slices on 1 side only. Spread the untoasted sides lightly with butter, then top 4 slices with the ham and sliced cheese. Press the remaining 4 bread slices on top, toasted sides up, and spread with the cheese mixture.
Broil about 2 minutes until the sauce is bubbling and golden brown. Serve at once.