French onion soup with croque monsieur croûtons
A French classic served with croque monsieur croutons that soak in the soup.
For the French onion soup
For the Gruyère croûtons
To make the French onion soup, heat the butter in a saucepan and add the onions, lardons, thyme, garlic and bay leaf. Cook covered for 20 minutes over a low heat until the onions are soft. Stir in the yeast extract and cook for a minute. Stir in the flour and whisk in the stock. Bring to the boil, season with salt and pepper, reduce the heat and simmer for 5–10 minutes.
To make the Gruyère croûtons, melt the butter in a saucepan and then stir in the flour. Slowly whisk in the milk and cream. Add most of the grated cheese and stir until melted. Season with salt and add the cayenne pepper. Leave to cool.
Lightly toast the bread on both sides. Brush half the slices with Dijon and mayonnaise. Add some ham, cheese slices and then sandwich with the remaining slices of bread. Top with the béchamel and remaining grated cheese. Preheat the grill to hot and cook until melted and golden.
Serve the soups in bowls, with a croûton in each soup and the rest alongside.