Cheesy Leeks dished into bowls from a pan

If you want a comforting, easy and delicious side dish, look no further than these cheesy leeks. A great accompaniment to a roast dinner and a fabulous alternative to cauliflower cheese, this dish combines sweet sauteed leeks in a bubbling white cheese sauce, topped off with crispy breadcrumbs and almonds.

What is it?

This dish is basically a leek gratin. A gratin is simply a dish that is baked in a shallow container and topped with a browned crust, often breadcrumbs.

The leeks are first sauteed to add flavour and then a bechamel sauce is prepared to pour over the top. If you’re unfamiliar with this name, it is very simply a white sauce that is used in a lot of different recipes, such as lasagne, or as a base for other sauces such as this parsley sauce.

A bechamel is made by first preparing a roux (more information below) and then adding milk. For this recipe, you add garlic, cheese and a little thyme to the bechamel for extra flavour and texture. The sauce is poured over the leeks in a baking dish and topped with more cheese and breadcrumbs before popping in the oven.

Cheesy leeks in a pan with grated cheese next to it

How do I make a roux?

A roux (pronounced ‘roo’) might sound scary but is incredibly simple and quick. It’s a mix of flour and fat and is used to transform a sauce from thin into luxuriously thick and rich.

Most commonly you will see recipes using plain flour and butter for the fat. Melt the butter over medium heat (don’t let it brown) and then once it is fully liquid add the flour. Whisk the mixture into a thick paste and then cook for two minutes to remove the raw flour taste without allowing the paste to brown. For these cheesy leeks, I also add a little garlic to the melted butter to add extra flavour to the dish.

You can also get differing degrees of colour for a roux – from white to blonde through to dark. The only difference is how long you cook the roux. For this recipe, you need a white roux, which is cooked for just a couple of minutes.

What can I serve it with?

This recipe is perfect for serving with a roast or with meat such as steak or chicken. A few good ideas to try are:

Cheesy leeks in a pan with bowls in the background

Can I make it in advance?

IIf you want to make this in advance, then it is best to prepare everything up until the point it is about to go in the oven. Then allow the dish to cool and store, covered, in the fridge. It will keep this way for 2 days and then you can simply pop it in the oven when you want to serve it.

Leftovers can be kept in the fridge and reheated within 3 days. However, you will lose the crunch from the breadcrumbs and the texture of the sauce will be less smooth. I don’t recommend freezing this dish. While it will be perfectly safe to eat, you may find that the sauce becomes watery when thawed, and it will be soggier.


For a full list of ingredients with weights and measurements jump to the printable recipe card.

Cheesy leeks Ingredients
  • Leeks, tops removed, cleaned, and sliced into 2.5cm/1in pieces
  • Unsalted butter
  • Garlic, finely chopped
  • Plain/all-purpose Flour
  • Milk whole milk will give the creamiest result but skimmed can be used instead
  • Mature cheddar cheese
  • Fresh thyme, leaves stripped from stems
  • Panko breadcrumbs
  • Flaked almonds


Recipe Variations

There are lots of different variations and flavours you can try with this recipe:

  • Add a little Dijon mustard to the cheese sauce for a warming flavour addition.
  • Sprinkle some nutmeg into the sauce or on top of the gratin for extra flavour.
  • Use dried breadcrumbs instead of panko. While panko crumbs give the crispiest result, dried breadcrumbs can be used if that’s what you have available.
  • Substitute the thyme for rosemary or sage for a flavour variation.
  • Experiment with different cheeses, swap the cheddar or blend with red Leicestershire, parmesan, gruyere or any other hard cheese you like!

How to make it

For more detailed recipe steps with tips jump to the printable recipe card.

Recipe Steps
  1. Preheat the oven to 200C/400F.
  2. Sauté the leeks until golden. Transfer to a baking dish.
  3. Add the butter to the pan and melt. Add the garlic and cook for a further minute.
  4. Make a roux by whisking the flour into the butter and garlic. Cook for 2 minutes.
  5. Add the milk to the roux a little at a time, constantly whisking.
  6. Add two-thirds of the cheese and the thyme to the sauce. Stir until the cheese has melted and the sauce is thickened. Season to taste.
  7. Pour the sauce over the leeks and then scatter over the remaining cheese. Top with the breadcrumbs and crumble the almonds over the top.

Looking for more great side dish recipes? Try:

Products that work well for this recipe:

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Cheesy Leeks dished into bowls from a pan

Cheesy Leeks

  • Author: caroline
  • Total Time: 50 minutes
  • Yield: 2 1x
  • Diet: Vegetarian


A beautiful addition to a roast dinner & a fabulous alternative to cauliflower cheese, these cheesy leeks combine sweet sauteed leeks in a cheese sauce.

The default recipe serves 2 as a side.


  • 1 tbsp olive oil
  • 500g cleaned and trimmed leeks, cut into 23cm long pieces
  • 20g unsalted butter
  • 1 clove garlic, finely chopped
  • 20g plain flour
  • 375ml / 1.5 cup cold milk (see note 1)
  • 80g cheddar cheese (see note 2)
  • 1 tbsp fresh thyme leaves, stripped from stems (see note 3)
  • 20g panko breadcrumbs (see note 4)
  • 1 tbsp flaked almonds



  1. Preheat the oven to 200C/400F.
  2. Heat the oil in a large frying pan/skillet over medium-high heat. Add the leeks and saute until starting to turn golden. Remove the leeks and transfer them to a baking dish.
  3. Next, make a roux in the same pan. Add the butter to the pan and, when melted, add the garlic and cook for a minute. Don’t allow the butter to brown and reduce the heat if needed.
  4. Add the flour to the pan and whisk until you have a paste. Cook for 2 minutes, stirring regularly. 
  5. Add the milk to the pan a little at a time, whisking each addition until fully incorporated. 
  6. Add two-thirds of the cheese and thyme to the sauce. Cook for a further couple of minutes stirring constantly until the cheese is fully melted into the sauce and it has thickened. Season to taste.
  7. Pour the sauce over the leeks and then top with the remaining cheese and the breadcrumbs. Crumble the flaked almonds over the top.
  8. Bake in the oven for 25-30 minutes, until golden on top.


  1. Whole milk will give the creamiest texture, but you can use semi-skimmed if preferred. Nutrition information is calculated using whole. 
  2. You can substitute the cheddar cheese or use a mix with other hard cheeses. Great options are red Leicestershire, parmesan or gruyere.
  3. You can use dried thyme instead of fresh, however, use half the amount as it is more pungent.
  4. Regular dried breadcrumbs can be used instead, however, panko will give a crispier texture.
  • Prep Time: 10 minutes
  • Cook Time: 40 minutes
  • Category: Side
  • Method: Hob / Oven
  • Cuisine: British


  • Serving Size: 1
  • Calories: 585
  • Fat: 38g
  • Carbohydrates: 43g
  • Protein: 21g

Keywords: side dish, vegetables, leeks, cheese, easy, roast dinner, vegetarian

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