Salmon and asparagus with parsley sauce

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Creamy, comforting and easy, this parsley sauce is perfect for serving with fish, shellfish or in a seafood pie. It’s super humble, requires a handful of ingredients and can be made in less than 20 minutes. As the flavour is quite delicate and mild it is bound to be loved by the fussiest of eaters and will pair well with a multitude of sides.

What is it? 

Parsley sauce is a classic British recipe that contains, you guessed it, parsley. The parsley is added to a white sauce which is essentially a bechamel (a white sauce made with a roux and milk). At its most basic you simply add parsley to the bechamel, although I like to add a little extra flavour with the addition of mustard and lemon juice plus a little cream to make the sauce silkier and richer. 

How do I make a roux?

A roux (pronounced “roo”) is a staple of many dishes and is used to thicken sauces and gravy. It might sound complicated, but it’s actually super simple. You need equal weights (not volumes) of flour and fat. I typically use butter, but you can alternatively use oil or fat.

While there are varying levels of roux you can make (from light to dark), this recipe needs a light roux, which takes around 3 minutes to make. Told you it was simple!

To prepare the roux, simply melt the butter in a pan and then reduce the heat a little (you don’t want it to turn brown.) Add the flour to the pan and use a whisk to mix it together. Keep cooking for about 2 minutes to remove the raw flour taste, whisking regularly. Et voila – you have your roux!

When thickening sauces, it is best to mix a hot roux with cold liquid or vice versa. Therefore, use cold milk when making this parsley sauce.

What can I serve it with?

You can serve this parsley sauce with a host of different things. The most popular use for parsley sauce is fish. Grilled cod or pan-fried salmon are both great choices. You could also serve it with a grilled chicken breast for added flavour and creaminess. Variations of parsley sauce are also used in fish pie. Check out this fish pie with egg recipe for inspiration.

Naturally, a good fish supper needs some potato or vegetable side dishes. These are all great ideas that will pair well without distracting from the main event:

Parsley Sauce in a pan with salmon and asparagus on a plate

Can I make this with dried parsley?

You can’t beat fresh parsley with this sauce. It will be smoother and taste brighter, but you can swap the fresh parsley for dried if that’s all you can get your hands on.

When using dried herbs use half the amount as they are more pungent. You may want to reduce this even more, so I recommend adding a quarter of the parsley, tasting, and then adding more if needed.

Can I make it with something else instead of parsley?

If you are looking for a similar sauce but can’t find any parsley, then there are a few great alternatives you can try:

  • Chervil
  • Dill
  • Basil
  • Tarragon (also check out this tarragon chicken recipe which is absolutely delicious)

How can I keep parsley fresh for longer?

Don’t you hate it when you buy a fresh vivid green bunch of parsley and it’s wilted and depressed the next day? Here is a great hack that will help you keep your herbs fresher for longer. This works with parsley, mint, coriander and more.

  1. Wash the parsley, so you can grab and go when you need it, and then pat it dry gently with paper towel (it doesn’t need to be bone dry, just not dripping wet).
  2. Fill a glass around half full with water and place the parsley stems in the water, as you would with a vase of flowers. If the stems are on the long side, then you can give them a snip to shorten.
  3. Grab a large food or freezer bag and place it over the top of the parsley. Secure the bag with an elastic band around the glass.
  4. Pop the glass in the fridge and wonder at how it looks great for anything up to 10 days!

I also love to use these herb keepers, which work in the same way, but make my fridge feel a little more organised!

How long does the sauce keep?

The great thing about this sauce is that you can make it in advance and reheat it with virtually no effect on the taste or texture (you may actually find the taste a little richer a day or two after making it!) Keep the sauce in a sealed container in the fridge for up to 3 days.

You can also freeze leftovers for up to 3 months. Defrost thoroughly before reheating and reheat on the hob/stove over medium heat.


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

Parsley Sauce Ingredients
  • Butter – unsalted so you can control the amount of salt you want in the sauce
  • Plain / all-purpose flour
  • Milk – both whole or semi-skimmed milk will work. Whole milk will provide a slightly richer flavour to the sauce
  • Single/whipping cream – optional but adds extra silky creaminess to the sauce
  • Lemon juice
  • Mustard – optional, choose a smooth Dijon mustard for best results
  • Parsley, finely chopped – can be substituted for dried but use half the amount (see notes above)

How to make it

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

Recipe Steps
  1. Melt the butter and then add the flour and whisk into a paste. Cook for 2 minutes.
  2. Add the milk a little at a time, until fully combined.
  3. Stir the cream, mustard and lemon juice to the sauce and combine.
  4. Bring the sauce to a low simmer and cook for around 5 minutes until thickened.
  5. Stir the parsley into the sauce and season to taste.

Looking for more great sauce recipes? Try:

  • Champagne sauce (a creamy and decadent choice for seafood)
  • Diane sauce (perfect with a juicy steak)
  • Red wine jus (great with red meats)
  • Balsamic glaze (lovely for drizzling over chicken or vegetables)
  • Italian salsa verde (great for adding a burst of flavour to seafood, chicken and more)

Products that work well for this recipe:

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Salmon and asparagus with parsley sauce

Parsley Sauce

  • Author: caroline
  • Total Time: 20 minutes
  • Yield: 4 1x
  • Diet: Vegetarian


Creamy, comforting & easy, this parsley sauce is perfect for serving with fish, shellfish or in a seafood pie. It can also be made in less than 20 minutes!

The default recipe serves 4


  • 25g / 0.9oz unsalted butter
  • 25g / 0.9oz flour
  • 500ml / 2 cup milk (see note 1)
  • 60ml 1/4 cup single/whipping cream
  • 2 tbsp lemon juice
  • 2 tsp dijon mustard (see note 2)
  • 34 tbsp finely chopped fresh parsley (see note 3)


  1. First, make a roux. Heat the butter in a saucepan or large frying pan over medium heat. Once fully melted add the flour and whisk together until you have a thick paste. Cook for 2 minutes, whisking regularly.
  2. Pour the milk in, a little at a time, whisking constantly until it is all added and the sauce is smooth.
  3. Add the cream, lemon juice and mustard if using. Whisk until smooth and season to taste.
  4. Reduce the heat so the sauce is slightly simmering – don’t let it boil or the milk will singe on the bottom of the pan. Continue cooking for around 5 minutes until thickened.
  5. Stir in the parsley and cook for a further minute. Add a little more seasoning if needed. Spoon over fish or chicken to serve.


  1. You can use either full fat or semi-skimmed milk for this recipe. Whole milk will have a slightly richer taste.
  2. You can leave the mustard out if you prefer. If you do use it make sure to use smooth mustard rather than one with whole grains.
  3. While fresh parsley gives the best taste, you can use dried parsley. Use around half the amount and add a little at a time, tasting as you go, until you reach the desired amount. 
  4. The sauce can be kept in a sealed container in the fridge for up to 3 days. It can also be frozen for up to 3 months. Defrost thoroughly before reheating on the hob/stove. 
  5. Nutritional information is based on semi-skimmed milk
  • Prep Time: 10 minutes
  • Cook Time: 10 minutes
  • Category: Sauce
  • Method: Hob / Stove
  • Cuisine: British


  • Serving Size: 1
  • Calories: 165
  • Fat: 10g
  • Carbohydrates: 12g
  • Protein: 6g

Keywords: parsley sauce, creamy, herbs, sauce, side, fish, seafood

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