Equipment
Ingredients
Leeks and Ham
- 8 leeks, trimmed, white and light green parts only
- 8 cooked ham, sliced thinly
Mornay Sauce
- 50 g unsalted butter
- 50 g all-purpose flour
- 500 ml whole milk, warm
- 10 g dijon mustard
- 1 g ground nutmeg, freshly grated
- 150 g gruyere cheese, freshly grated
- salt
- black pepper
Topping
- 30 g panko breadcrumbs
- 30 g parmesan cheese, freshly grated
Nutrition (per serving)
Method
Bring a large pot of salted water to a boil. Slice off the dark green tops and the root ends of the leeks. Peel away the tough outer layer.
Add the prepared leeks to the boiling water and cook until tender when pierced with a knife, about 15 minutes.
Carefully remove the leeks from the water using tongs or a slotted spoon. Place them on a clean kitchen towel and gently press them to extract as much excess water as possible.
Preheat the oven to 200°C/400°F. Grease a 9x13 inch baking dish.
Wrap each drained leek tightly in a slice of ham. Arrange them in a single layer in the prepared baking dish.
Melt the butter in a medium saucepan over medium heat. Whisk in the flour and cook for 2 minutes to cook out the raw flour taste, forming a pale roux.
Gradually whisk in the warm milk, pouring in a steady stream while whisking constantly to prevent lumps. Simmer for 5 to 7 minutes until the sauce heavily coats the back of a spoon.
Remove the saucepan from the heat. Whisk in the Dijon mustard, nutmeg, and the grated Gruyere cheese until completely smooth. Taste and season with salt and black pepper.
Pour the cheese sauce evenly over the ham-wrapped leeks in the baking dish. Mix the panko breadcrumbs and grated Parmesan cheese together, then scatter this mixture over the top.
Bake in the preheated oven at 200°C/400°F for 20 minutes, until the sauce is bubbling heavily around the edges and the crumb topping is deep golden brown.
Let the casserole rest for 5 to 10 minutes before serving to allow the sauce to set slightly.
Chef's Notes
- Draining the leeks is the single most important step in this recipe. Leeks act like sponges; failing to press them dry will result in a split, watery sauce.
- For the highest quality Mornay sauce, always grate your own Gruyere from a block. Pre-shredded cheeses are coated in starches that interfere with a smooth melt.
- If your leeks are particularly thick, you may want to slice them in half lengthwise before wrapping them in ham, which reduces the boiling time and makes them easier to eat.
- Warming the milk before adding it to your roux helps prevent seizing and lumps, leading to a silkier bechamel base.
Storage
Refrigerator: 3 days — Store in an airtight container. The breadcrumb topping will lose its crispness.
Reheating: Reheat in a 180C oven for 15-20 minutes until bubbling and heated through.
