Butter-Basted Roast Chicken with Herby Leeks

There are more complicated ways to roast a chicken and most of them are a waste of a Sunday. This is the version we come back to: a herb butter pushed under the skin, a bed of leeks doing the work of a trivet and a side dish at the same time, and twenty minutes of resting that people always want to skip and never should.

Serves four, with enough left for sandwiches on Monday.

What you'll need

A good free-range chicken, around 1.8kg. 120g Kerrygold Unsalted Butter, softened. 4 large leeks, trimmed and cut into thick rounds. 2 tablespoons chopped tarragon. 2 tablespoons chopped flat-leaf parsley. 1 tablespoon thyme leaves. Zest of one lemon, plus the squeezed-out lemon half for the cavity. 2 cloves garlic, crushed to a paste with a little salt. 150ml dry white wine or chicken stock. Sea salt and plenty of black pepper.

Step one: make the herb butter

Beat the softened Kerrygold Unsalted Butter with the tarragon, parsley, thyme, lemon zest, garlic paste, a good half-teaspoon of salt and a generous grind of pepper. We use unsalted here deliberately — you're seasoning the skin separately and you want to control the salt yourself.

Set about a third of the butter aside for the leeks and the pan sauce.

Step two: get the butter under the skin

Take the chicken out of the fridge an hour before you start. A cold bird cooks unevenly and the skin never quite catches up.

Slide your fingers between the skin and the breast meat at the neck end, working gently to loosen a pocket over each breast and, if you can manage it, down over the tops of the thighs. Go slowly — tearing the skin isn't fatal, but intact skin crisps far better.

Push the herb butter into those pockets and press it flat from the outside so it spreads in an even layer. This is the whole trick of the dish. As the chicken roasts, that butter melts down through the breast meat, basting it continuously from the inside, which is a far more reliable job than you spooning fat over the outside every twenty minutes.

Rub the outside of the skin with a little more butter and season it well with sea salt.

Step three: build the tin

Scatter the leek rounds across the base of a roasting tin, dot with the reserved herb butter, season, and toss. Sit the chicken directly on top. Put the squeezed lemon half and any leftover herb stalks inside the cavity.

The leeks act as a trivet, lifting the bird so the air circulates underneath, and they slowly collapse into the chicken fat and butter until they're sweet and almost jammy.

Step four: roast

Roast at 200C fan 180C, gas mark 6, for 20 minutes per 500g plus an extra 20 minutes — so around an hour and a half for a 1.8kg bird. Baste once at the halfway mark with the buttery juices in the tin, and give the leeks a stir while you're there.

It's done when the juices from the thickest part of the thigh run clear, or when a thermometer in the thigh reads 74C. If the breast is browning too fast, lay a loose sheet of foil over it for the last twenty minutes.

Step five: rest, then make the sauce

Lift the chicken onto a warm board and rest it for a full 20 minutes, loosely covered. Do not shorten this. Resting lets the juices redistribute through the meat instead of running out onto the board the moment you carve.

Meanwhile, put the tin over a medium heat on the hob. Pour in the wine or stock and scrape up every brown sticky bit from the base with a wooden spoon. Let it bubble and reduce by about half, then whisk in a final knob of Kerrygold Unsalted Butter off the heat to give it gloss and body. Taste and season.

To serve

Carve the chicken and spoon the leeks and their sauce around it. Roast potatoes are the obvious companion and we're not going to argue against them, but honestly a loaf of good bread to mop the tin is closer to the point of the dish. Anything left over goes into a sandwich with cold butter and the last of the leeks, which may well be the best part of the whole exercise.