Description
Discover how to make a rich, creamy Baked Leek Gratin layered with buttery leeks, Gruyère cheese, and a golden breadcrumb topping. A comforting, elegant side dish for any occasion.
Ingredients
Scale
- 8 tablespoons unsalted butter, divided
- 5 to 6 leeks, washed, sliced, and roughly chopped (use mostly the white parts and some green)
- 1 large shallot, chopped
- Salt and pepper, to taste
- 3 tablespoons all-purpose flour
- 2 cups whole milk
- ½ teaspoon cayenne pepper
- 1 tablespoon lemon juice
- 1 cup Gruyère cheese, grated
- ⅔ cup fresh breadcrumbs
Instructions
- Prepare the Leeks:
Trim the root ends and tough dark green tops of the leeks, keeping the white and light green parts. Slice lengthwise, rinse thoroughly to remove any grit, and chop roughly. - Cook the Leeks and Shallots:
In a large skillet, melt 4 tablespoons butter over medium heat. Add the leeks and shallots with a pinch of salt and pepper. Sauté for 8–10 minutes, stirring occasionally, until the leeks are soft and lightly golden. Remove from heat and set aside. - Make the Sauce (Béchamel):
In a medium saucepan, melt the remaining 4 tablespoons butter over medium heat. Whisk in the flour and cook for 1–2 minutes until lightly foamy. Slowly pour in the milk, whisking constantly to avoid lumps. Continue whisking until the sauce thickens and coats the back of a spoon — about 5 minutes. - Season the Sauce:
Stir in the cayenne pepper, lemon juice, and a pinch more salt and pepper. Add ½ cup Gruyère and stir until melted and smooth. - Assemble the Gratin:
Preheat oven to 375°F (190°C). Lightly butter a baking dish. Spread the sautéed leeks evenly on the bottom, then pour the cheese sauce over them. Stir gently to combine. - Add the Topping:
In a small bowl, mix breadcrumbs with the remaining ½ cup Gruyère and a drizzle of melted butter if desired. Sprinkle evenly over the top. - Bake:
Bake uncovered for 20–25 minutes, until the top is golden brown and bubbling around the edges. - Serve:
Let rest for 5 minutes before serving. Garnish with chopped parsley or thyme if desired. Serve warm as a rich side or vegetarian main.
Notes
Clean leeks thoroughly — they often hide grit between layers.
Whisk the sauce constantly to avoid lumps and achieve smooth creaminess.
Freshly grate the cheese — it melts better and tastes richer.
Bake until golden and bubbling for the perfect balance of cream and crunch.