Compound butter is butter combined with flavouring ingredients.
It can be used to butter canapés, finish off sauces, or put in pats for melting on a piece of meat or fish in place of a sauce. There are savoury versions and “sweet” versions.
Compound butter combinations include:
- parsley and shallot butter for escargots;
- blue cheese, shrimp or anchovy for small canape toasts;
- red pepper, beet or cucumber for specialty finger sandwiches;
- strawberry, orange or fig compound butter for melting on waffles;
- orange-mint butter for chocolate muffins warm out of the oven;
- apricot butter for hot crumpets;
- lemon parsley butter for asparagus, broccoli or Brussels sprouts.
Compound Butter can be a make-ahead, elegant alternative to sauces, not to mention a unique one, because it has gone out of fashion.
In restaurants, restaurant kitchen workers used to make Compound Butter in a mortar and pestle, but now they’ll just use a food processor. With smaller quantities for the home, you may well want to revert to using a mortar and pestle. The restaurant people will then roll a batch of Compound Butter up tightly up in a log shape, wrap it in waxed paper, greaseproof paper or plastic wrap with the ends twisted tightly, then refrigerate it and draw on it as needed. A warm knife is used to slice off medallions for use.
It can be a lot of work, though, to make up Compound Butter just for a few small servings at home. Most recipes give quantities more appropriate for a restaurant simply because it is very hard to make it in small quantities — all the varied ingredients needed increase the overall end quantity. And if you were to give recipe users the kind of measurements required to end up with, say, 1 tablespoon of Compound Butter, you’d have to give them quantities of stuff such as 1 g of garlic, 1/2 g of parsley, etc. — and they’d think the recipe writer had lost the plot, in expecting those kinds of measurements outside a lab. Consequently, many people just give in and make up a log of it at home, wrap it up well, and freeze it, cutting off pieces as needed.
In France, in fact, you can buy ready-to-use logs of Compound Butter (with brands such as Maître Gustille) in the chiller section, in 1/2 pound (250 g) quantities.
If frozen Compound Butter softens while you are cutting, making it harder to work with, you can pop it back in the freezer until it is hard again (it’s okay to refreeze it.)
You can also just form your Compound Butter into small balls and freeze. To use the balls, cut them in half — a flat surface is important if you plan to use the butter as a garnish on something like a hot steak — the flat surface helps prevent it rolling off as it melts.
If the food item you are putting it on is not hot enough to melt the butter, pop the food item with the butter on it under a broiler (aka grill in the UK) for about 60 seconds or so to get it started melting (put the food on something safe to go under a broiler / grill — not your finest Royal Crown Derby.) Or, try covering the food item with the butter on it for a minute or two.
The most popular Compound Butter used frequently in homes, perhaps owing to its simplicity, is garlic butter.
Compound Butter is best made at least a day ahead of time, to allow time for the flavours to marry.
In making one, you first make a “pommade” — creamed butter, then combine it with the flavouring ingredients.
To be creamed, the butter needs to be taken out of the fridge in advance, and warmed up to about 70 F (21 C), or you can soften butter more quickly by whizzing it in a food processor.
Most Compound Butter recipes call for unsalted butter, even if they then call for salt later in the recipe. The idea is to give you control over the degree of saltiness.
Any fresh herbs should be thoroughly dried of any water left after washing. If you are processing fresh herbs in a food processor, process them coarsely. You still want them to be seen, not turn into a green liquid mush.
Store Compound Butters (depending on what is in them) for up to 5 days in the refrigerator, 6 months in the freezer. Instead of freezing a batch in one long log, you may wish to cut it into smaller lengths, and freeze separately.
Compound Butter was common in all French-tradition cooking up until the second half of the 20th century, until the trend of de-emphasizing butter and all ingredients seen as fatty, heavy, and old-fashioned began.