Caper Sauce

This is a sauce for the cold months. The kind of thing your grandmother might have made without thinking, ladled over a piece of boiled mutton on a Sunday in February when the windows had gone opaque from the cooking. It's been out of fashion for decades, which is most of the reason I'm writing about it. Some things deserve to come back.

Caper sauce is a white sauce with capers in it. That's the whole idea. But the description undersells what happens when the sharp, briny pop of the capers hits the soft, buttery weight of the sauce, with a squeeze of lemon to wake it up and a handful of parsley to keep it honest. It transforms a plain piece of boiled meat into something you actually want to eat. It rescues a poached fish from politeness. Spoon it over a head of steamed cauliflower and you have dinner.

The trick, if there is one, is the cooking liquor. A spoonful of the water the meat was cooked in, or the broth from a poached fish, ties the sauce to the dish in a way that plain milk never quite manages. This is old cookery thinking. Use what's already in the pan. Don't waste what's already flavoured.

I wrote it down in the notebook the first time I made it for someone who'd never tried it: caper sauce, mutton, late January, snow on the back step. They asked for the recipe before they'd finished their plate. A recipe is a conversation, not a contract, and this one has been having the same quiet conversation for two hundred years.