Imagine this: Melt-in-your-mouth leeks baked in a luxuriously creamy sauce with cheese infused with nutmeg and mustard. More grated cheese and a golden brown, crispy breadcrumb topping adds the perfect finishing touch. This, my friends, is the epitome of British comfort food – British Style Cheesy Leeks, a perfect side dish to showcase seasonal leeks.

A closeup of baked leeks in a cheese sauce in a white baking dish

This cheesy leeks recipe is undoubtedly one of the best I’ve ever made. Yes, I said it and I stand by it. The combination of mild, tender leeks with a flavorful and easy cheese sauce is simply irresistible.

When are leeks in season?

Leeks are grown and harvested in the cooler months, with the season typically running from October to May.

A large spoonful of leeks in a cheese sauce

Embrace French Technique: Leeks Au Gratin

This “leeks au gratin” recipe is a classic French method and a beloved way to prepare leeks in the U.K. Don’t be fooled by its simplicity – a creamy cheese sauce is infused with secret flavor boosters that elevate the dish without overpowering the delicate leeks in cheese sauce.

What to Serve with Baked Cheesy Leeks

Baked in a creamy cheese sauce and crowned with golden brown, crispy breadcrumbs, leeks transform into a delicious side dish for your roast dinner (think Sunday roasts, beef, chicken, or lamb).

Yellow mustard and nutmeg are my secret weapons. These unexpected ingredients play a supporting role, enhancing the overall flavor profile without stealing the spotlight. Both options emphasize the role of mustard and nutmeg while avoiding negativity about not directly tasting them.

The sauce starts as a classic white sauce: milk thickened with flour.  I always elevate this base with a touch of nutmeg, introducing a subtle sweetness and depth.  Yellow mustard adds a different and delicious dimension  a delightful complexity, transforming this sauce into a dream pairing for macaroni cheese dish or cauliflower cheese.

An overhead view of a square, white baking dish filled with cheesy leeks.

One-Pan Cheesy Leeks: A Streamlined Delight

This recipe takes a one-pan approach for ultimate ease.  We start by softening leeks in melted butter over medium heat, keeping them pale without browning. This forms the base for our creamy cheese sauce. 

Once the sauce is ready, simply transfer everything to a baking dish and pop it in the oven. If you’re using an oven-safe pan, you’ve got a true one-pan wonder! This dish seamlessly transitions from stovetop to oven for a fuss-free feast. 

Cheese Choice for the Perfect White Sauce

Since we’re building a white sauce, a good white cheddar cheese is best. English cheddar if you can find it because it offers a beautiful creamy white color and a delightful flavor compared to yellow cheddar. Gruyère is another fantastic option, bringing its own unique twist.

Plant-Based Alternatives

Transform this recipe into a vegan version with a few simple swaps! Use your favorite plant-based butter, milk, and cheese alternatives.

Pan Size

You don’t need a large pan/baking dish for this recipe. I used my 8 x 8-inch (20 cm) ceramic baking dish.

If you’ve made this British Style Cheesy Leeks, please leave a comment below. You can also ask a question too.

Yield: 4

British Style Cheesy Leeks

A crispy breadcrumb topping and chopped parsley on top of leeks in cheese sauce

Tender leeks are baked in a creamy cheese sauce and topped with more cheese and breadcrumbs.

Prep Time 10 minutes
Cook Time 15 minutes
Total Time 25 minutes


  • 3 (50 grams) butter, unsalted * see note
  • 1 tablespoon light flavored oil
  • 3-4 large leeks (4 cups/365 grams), cleaned and sliced
  • ¼ teaspoon salt
  • 2 ½ tablespoons (20 grams) all-purpose/plain flour
  • 1 cup (236 ml) whole/full fat milk, warmed
  • 1 tablespoon yellow mustard
  • 1 teaspoon nutmeg, grated
  • 1 ¾ cups (100 grams) sharp white cheddar cheese, grated
  • 4 tablespoons (25 grams) breadcrumbs
  • Fresh parsley, chopped for garnish (optional)


  1. Preheat oven to 400°F/200°C.
  2. To a large pan, add the butter and oil over medium heat until melted and bubbly. Add the leeks and salt, cook, stirring often until slightly softened.
  3. Sprinkle in the flour and stir to mix into the butter, cook for a minute to cook out the raw taste. Slowly drizzle in the milk while stirring or whisking. Add the mustard and nutmeg, stir until smooth and starting to thicken.
  4. Pour into an 8 x 8-inch (20 x 20 cm) ovenproof baking dish and top with the remaining cheese and the breadcrumbs. Bake for 12-15 minutes until the top is golden brown. Serve with chopped parsley.


I prefer unsalted so I can control the salt level. If you use salted butter, salt to your taste level.

Nutrition Information



Serving Size


Amount Per Serving Calories 443Total Fat 33gSaturated Fat 17gTrans Fat 1gUnsaturated Fat 13gCholesterol 82mgSodium 612mgCarbohydrates 22gFiber 2gSugar 6gProtein 17g

This nutrition calculation is provided by Nutronix that is only a guideline and not intended for any particular diet.