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Parsley Sauce Perfect Served with Fish

Parsley sauce, a traditional British accompaniment for fish, similar to a bechamel it begins with a roux and is silky smooth and delicious!

You can turn this recipe all the way up to 11 by using the milk to steep smoked fish, then go on to use it to make your white sauce.

White parsley sauce poured from a jug over a fishcake.

Classic White Sauce for Fish.

Fish in parsley sauce was considered all sorts of lahdedah when I was growing up in the late 70’s and early 80’s in the UK.

It kinda fell out of fashion probably thanks to the arrival of the frankly awful frozen ready meals. They largely featured some tasteless white fish in a white gloop reminiscent of wallpaper paste.

But a classic roux-based white sauce with parsley is the base of every great fish pie and of course at the heart of cod mornay, smoked haddock pasta and my smoked haddock gratin.

But it is so much more than that, it is great as a stand-alone sauce and it is far easier than many would believe.

A lump-free, tasty, silky white sauce is so simple to make at home and I think that it is a great addition to a cooks armoury.

My version comes together in just 25 minutes and 10 minutes of that is letting the milk cool a little. That little break is the perfect time to cook yourself some fish!

White parsley sauce in a milk pan with butter and flour.

Frequently Asked Questions.

Is flavouring the milk essential?

No, it is not essential, but it does add a depth and dimension to what is essentially flour, butter and milk with some herbs.

Can I flavour the milk with anything else?

Yes, smoked fish is one of the best and it makes for a jaw dropping sauce.

You can keep the classic flavours and then pour over something like smoked haddock and allow it to cool. Or you can omit the onion and garlic and just flavour with the smoked fish.

Can I make white sauce in advance?

Yes and no! If you make it in advance you can cover it with cling film but push the cling film into the pan or bowl and make sure there is no air between the sauce and the film.

Any air and the sauce will form a “skin” which can be difficult to combine with the sauce. If your sauce does form a skin it is best to skim it off.

The sauce will also continue to thicken. As a result, you will probably need to add more milk to thin it down when reheating.

But for the very best results serve immediately.

White parsley sauce served with a smoked haddock fishcake.

Serving Suggestions.

Parsley sauce is a classic accompaniment to fish. It is wonderful with something like pan fried salmon or this herb crusted roast cod.

But I think that it works wonderfully with fishcakes!

If you have floated around here much you will know that I am rather fond of fish cakes!

I serve this wonderful sauce here with my smoked haddock fishcakes. But it would work equally well with my tinned mackerel fishcakes and my sardine and salmon fishcakes.

But don’t get hung up on fish, it is just as good with some simply cooked pork loin steaks or pork chops.

Don’t forget the good old chicken either, it is fab with roasted or poached chicken breast.

White parsley sauce poured over a fishcake.

Equipment Used

I only name-check brands of equipment if I think they make a material difference to a recipe. If you have any questions feel free to ask them in the comments section below the recipe.

  • Stovetop
  • 2 x 15cm or 6″ saucepans.
  • Chopping board.
  • Kitchen knife.
  • Weighing scales and or measuring cups and spoons.
  • Whisk or silicon spoon.
White parsley sauce poured over a fishcake.
Yield: 2 Servings

Parsley Sauce Recipe

Prep Time: 5 minutes
Cook Time: 20 minutes
Total Time: 25 minutes

Parsley sauce is a traditional British accompaniment for fish, a classic white roux is prepared before flavoured milk is gradually added to form the silkiest of sauces before getting freshened up with lots of fresh parsley.


  • 30g (2 Tbsp) Butter
  • 30g (¼ Cup) Flour
  • 300g (1¼ Cup) Full Fat Milk
  • 10g (⅔ Cup) Fresh Parsley
  • ¼ Tsp Salt
  • ¼ Tsp White Pepper

For flavouring the milk (Optional):

  • 1 Onion
  • 4 Cloves
  • 1 Garlic Clove
  • 1 Bay Leaf


  1. Peel and the onion and then push the pointed end of the cloves into the onion before placing it in a small (15cm or 6") milk pan.
  2. Bash the garlic with the flat side of a knife and add it to the pan and add the bay leaf.
  3. Pour over the milk and bring to a boil, then turn off and allow to cool for 10 minutes.
  4. Chop the parsley as finely as you can.
  5. In a second 15cm or 6" saucepan melt the butter over a medium heat without colouring.
  6. Add the flour to the melted butter and cook stirring constantly for 3-4 minutes, if the flour begins to go beyond light blond colour reduce the heat a little. Do not rush this step, you need to "cook out" the flour so that your sauce does not taste like raw flour.
  7. Remove the flavourings from the milk, then add the salt and white pepper and stir to combine.
  8. Add the milk little by little to the roux base starting with around 3 tablespoons, stir constantly as you add the milk and only add more once the previous addition is completely combined.
  9. Initially, the mix will look like it has split, but it will come together and form a paste. As you add more milk to the paste, it will thin to a beautiful white sauce.
  10. Be careful not to boil the sauce, if it is coming to a boil reduce the temperature a little.
  11. This recipe makes a thick sauce, if you want to thin it out a little add more milk.
  12. Stir through the chopped parsley and serve immediately.


If you want to use the milk to cook smoked fish pour over the fish immediately and do not allow to cool.

Nutrition Information:



Serving Size:


Amount Per Serving: Calories: 274Total Fat: 16gSaturated Fat: 10gTrans Fat: 1gUnsaturated Fat: 5gCholesterol: 44mgSodium: 474mgCarbohydrates: 27gFiber: 3gSugar: 10gProtein: 8g

Calorific details are provided by a third-party application and are to be used as indicative figures only.

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