Leek and Cheese Gratin

January. Rain on the window and the light gone by half four. The leeks at themarket this morning were beautiful, fat and pale with mud still clinging to the roots, the sort that feel heavy and cold in your hand and smell faintly of the earth they came from. I bought six without a plan and the plan arrived on the walk home: gratin.

A leek and cheese gratin is not a complicated thing. It doesn't pretend to be. You soften the leeks, make a cheese sauce, put one on top of the other, and bake it until it blisters. The leek does the real work here, going sweet and silky under that bubbling crust, and the sauce is just there to carry the cheese where it needs to go. A recipe is a conversation, not a contract. If you want to add a scraping of garlic to the sauce, do. If you've got some thyme, tuck it in with the leeks. Your kitchen, your rules.

This is the kind of supper I come back to when the weather turns and the evenings close in. There are few better feelings than carrying a blistering dish to the table and watching someone's face when the smell hits them. We're only making dinner. But sometimes dinner is the whole point of the day.

I wrote it down in the notebook last Tuesday: leeks, cheese sauce, breadcrumbs, the good cheddar. Rain. Ate it with bread and didn't speak for ten minutes. That's a review.