Onion Sauce

This is a Sunday sauce. Specifically, the sauce that sits in a small jug next to a roast leg of lamb, waiting its turn while everyone helps themselves to potatoes and arguing about whether the meat is done. Onion gravy gets all the attention these days, but onion sauce is the quieter, older thing, and on the right plate it's better.

It's a béchamel, essentially, made with milk that has been gently bothered by a bay leaf and a few peppercorns, then thickened with a butter and flour roux and stirred through with onions that have been coaxed into softness over a low heat. Nothing about it is clever. Nothing about it needs to be. The onions go sweet without going brown, the milk goes silky, and the whole thing tastes of a kitchen that has been paying attention.

I grew up eating this with mutton, which nobody seems to cook anymore, and lamb, which everyone does. It works with both. It works with a piece of poached chicken on a tired Tuesday. It works with a baked potato if that's the kind of evening you're having. A recipe is a conversation, not a contract.

I wrote it down in the notebook years ago and the note next to it says: "Sunday lamb. Rain. Three for dinner. Made the sauce. They asked for more." That's the whole brief, really.