Here’s a sandwich that’s basically all the good stuff—melty cheese, mustardy leeks, buttery bread, and a fried egg on top to seal the deal. The béchamel is silky and cheesy, the jambon adds just the right salty hit, and the leeks bring a little brightness with lemon and mustard. It’s easy to pull together but feels fancy enough to impress yourself or anyone you’re feeding. Perfect for brunch, lunch, or anytime you want something cozy and delicious without fuss.
Ingredients
For the Leek Mustard:
- 2 tbsp butter
- 2 leeks, finely chopped
- 2 tbsp mustard
- ½ tsp lemon zest
- 1 tbsp lemon juice
- Salt and pepper to taste
For the Béchamel:
- 1½ tbsp butter
- 1½ tbsp all-purpose flour
- 1¼ cup milk
- ½ tsp grated nutmeg
- ¼ cup grated Gruyère cheese
Additional Ingredients:
- 4–5 tbsp softened butter
- 300g jambon de Paris, thinly sliced
- 4 slices sourdough bread
- ¾ cup grated Gruyère cheese
- 2 eggs
- Fresh thyme or chives
- Salt and pepper to taste
Directions:
- In a cast iron pan over medium-low heat, melt butter and sauté leeks until soft and fragrant, about 7 minutes. Stir in mustard, lemon zest, and lemon juice. Cook for 2 more minutes. Season with salt and pepper. Set aside.
- To make the béchamel, melt butter in a small saucepan over medium heat. Whisk in flour to form a paste, cook for 1 minute. Add milk gradually, whisking continuously. Lower heat and cook until thickened, about 5 minutes. Add nutmeg and Gruyère, whisk to combine. Set aside.
- Butter one side of each bread slice. Place two slices, butter side down, on a surface and top with jambon. Close with the remaining bread, butter side up.
- Toast sandwiches in a hot pan over medium-high heat until golden and crisp, about 2 minutes per side. Remove from heat.
- Open sandwiches in the pan and add grated cheese and 3 tbsp of leek mustard per sandwich. Close again.
- Preheat oven to broil. Spoon ½ cup béchamel over each sandwich and broil until bubbling and golden. Watch closely to prevent burning.
- Meanwhile, fry eggs in a nonstick pan with a bit of butter to your desired doneness.
- Remove sandwiches from the oven, top each with a fried egg, and garnish with fresh herbs, salt, and pepper.
- Serve immediately and enjoy!
