Leek Gratin

Our leek gratin recipe calls for only three ingredients: leeks, heavy cream, and salty Pecorino Romano cheese. Don't let the short ingredient list fool you, though—it results in a rich and elegant side dish that's ideal for a holiday or special occasion. To achieve perfectly tender leeks that still hold their shape, you'll first boil them in the cream, which has the added benefit of reducing the liquid into a silky sauce, then bake them with the cheese until the whole thing is golden brown and bubbly. Our leek gratin makes a delicious accompaniment to seared or roasted proteins like fish, chicken, or pork, and it couldn't be simpler to pull together.

How to Prep Leeks for This Recipe

Since leeks grow underground, it's especially important to rinse them thoroughly before cooking to remove any grit.

1. Trim off the dark green leaves (freeze them for a future stock), but leave the root end attached—it'll help ensure the leeks hold their shape as they cook. Using a sharp knife, slice leeks in half lengthwise.
2. Run them under cool water, gently pulling open the layers to rinse out any dirt. Shake off excess water before cooking.

Equipment Needs for Leek Gratin

You'll only need a couple of pieces of kitchen equipment to pull together this heavenly gratin, including:

Cutting board: A sturdy cutting board is essential for preparing the leeks for this recipe. To keep it from sliding around on your counter, place a damp kitchen towel or a few damp paper towels underneath it.

Chef's knife: A sharp knife will make trimming and slicing the leeks a cinch. While you can use any size knife for this recipe, one with a larger blade—like a chef's knife—will give you the most control.

Large skillet: You can use a stainless steel, cast iron, or nonstick skillet for this recipe, just make sure it's large enough to hold the 16 leek halves comfortably (they can overlap as needed). Since the skillet will need to be covered for the first portion of the cooking process, a tight-fitting lid is recommended. If you don't have a lid large enough, you can cover the skillet tightly with a piece of foil.

Baking dish: To bake the cheese-topped leeks, you'll need a shallow, two-quart baking dish. We recommend using a rectangular one measuring 11 inches by 7 inches, which will fit them perfectly, though a square or oval will also work.

How to Make Leek Gratin Ahead

You can prepare this recipe through step 2 up to one day ahead, then bake it before serving. After simmering the leeks until they're tender, transfer them and the sauce to a baking dish, then let cool completely; cover and refrigerate.

When you're ready to resume cooking, remove the baking dish from the fridge while you heat the oven. Top with cheese and bake according to recipe instructions.