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  • Bute St Seafoodie

Caper Butter Sauce

Updated: May 24, 2020

"Honest bread is very well - it's the butter that makes the temptation."

Douglas Jerrold (1803-1857)

I've said in previous posts (see, for example Grilled Brill Fillets with Anchovy Butter) that I've never really cared for butter sauces. Well, much like anything in food, when I suggest that I may not like something, I find all too often that what I really mean is that I do like it, I just like other things more. So, yes, this is a moment of submission.

At the heart of this sauce is a classic Beurre Blanc, a sauce brought into this world in the Loire Valley by Clémence Lefeuvre in the early 20th century. Legend has it that its birth was a result of her unintentional omission of eggs whilst making a Béarnaise sauce to accompany a pike destined for the table of the Marquis de Goulaine.

This particular recipe is substantially based on one by Debbie Major for Delicious Magazine with additional reference to"Sauces, Savoury & Sweet" by the god of sauces himself, Michel Roux (RIP). It is easier to make than some might have you think and is sensational with steamed or poached white fish.

Creating emulsion sauces is often considered a daunting task and I can say that I have split a few in my time. What I have learnt (and the article "Beurre Blanc Breaks" is a handy reference) is first, to keep the recipe quantities in the prescribed proportions and second, to carefully manage the temperature of the pan while incorporating the fat.

Basically, once the liquid part of the sauce is hot, the temperature need be no higher than that required to incorporate the butter, in the case of this sauce. If the butter becomes too hot the sauce is likely to split and will not emulsify. It is therefore better to err on the side of caution and keep the pan on the cool side, reintroducing heat if it cools so much that the butter will not melt.

Once the basic Buerre Blanc has been made, various flavourings can be added to it (within reason) without risk of the sauce splitting. Here capers and parsley are added to create this caper butter sauce, but I have included some other variations further down in the post and will continue to update the list as and when.

Because of the minimal number of ingredients in this recipe it benefits immeasurably from the use of the best quality ingredients possible, especially the butter but notably also the wine vinegar. This sauce requires fairly generous seasoning and it is probably reasonable to say that over-seasoning will result in less disappointment than under-seasoning. A teaspoon of mustard provides a welcome piquancy in the finished result if that should appeal.

Caper Butter Sauce

Ingredients (Serves 2)

25g shallot, very finely chopped

2 tbsp dry white wine

1 tbsp white wine vinegar (best quality)

90ml (6 tbsp) water

1 tbsp double cream

75g unsalted butter (best quality), cut into 1cm dice and chilled

2-3 tsp capers, drained and rinsed

1 tbsp parsley, finely chopped

Salt and freshly ground black pepper

Lemon juice, quantity to taste


  1. Put the shallot, white wine, vinegar and water in a small saucepan and bring to the boil. Over a medium-high heat allow the liquid to reduce until it has all but evaporated.

  2. Add the double cream and heat briefly. At this point the sauce can be removed from the heat to prepare other parts of a meal, in which case, 5 minutes before serving time, return the pan to the boil and continue with the recipe. Otherwise, just continue.

  3. Reduce the heat to low to medium and gradually add the lumps of butter, a few at a time, whisking them in completely before adding the next few. The heat should be no more than is required to incorporate the butter in a reasonable amount of time (10-20 seconds). If the sauce becomes too cold increase the heat briefly until it is warm enough to continue melting the butter. As the final lumps of butter are added the sauce should become smooth and creamy.

  4. Stir in the capers and parsley then adjust the seasoning with salt and pepper and lemon juice to taste. Serve within a few minutes.


  • Anchovy and caper sauce: Include 2-3 finely chopped salted anchovies (best quality) at step 4. This variation will likely require less salt and more lemon juice when seasoning.

  • Mustard sauce: Instead of (or in addition to) the capers, stir in 1-2 tsp Dijon (or other) mustard at step 4, and optionally omit the parsley.

  • Herb butter sauce: Replace the capers and parsley with 1-2 tsp finely chopped herbs of your choice. A scant 1 tsp tarragon alone would make a delicious sauce (even with poached chicken), but so too would any or all of the members of the fines herbes: tarragon, parsley, chervil and chives.


  1. "Sauces, Savoury & Sweet", Michel Roux (2009), pp. 102:


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