Step 1 Mix the marinade ingredients together and rub them well into the lamb; leave to marinade for at least 2 hours, preferably overnight.

Step 2 Heat the oven to 220°c fan; place the lamb in a roasting tray, covering well with the marinade, and roast for 20 minutes.

Step 3 Remove the tin from the oven and tuck the whole garlic cloves and 3 sprigs of the thyme under the lamb.

Step 4 Reduce the oven to 130°c fan, then add a splash of water to the roasting tin and return the lamb to the oven. Roast slowly for around 3-4 hours, or until the lamb feels completely tender with a skewer.

Step 5 As it roasts, add another splash of water every hour or so, just to keep the bottom of the pan from drying out, and baste the lamb as it cooks.

Step 6 Lift the lamb out onto a warmed plate, cover with foil and, keep it warm. Keep the contents of the roasting tin to one side.

Step 7 Place a heavy-bottomed pan over a medium hot, and gently fry off the sliced onion with the remaining sprig of thyme in some of the lamb fat from the roasting tin. Cook for around 15 minutes until thoroughly softened, but don’t let it go too brown.

Step 8 Add 500ml water to the roasting tray, scrape up as much of the sticky, caramelised contents as possible, and add to the saucepan along with the drained beans. Simmer very gently until the beans start to break down then remove them from the heat and season well.

Step 9 Serve the lamb alongside the creamy beans. I like to serve this with steamed samphire, tossed in melted butter with a squeeze of lemon juice and a generous amount of black pepper, or with English asparagus when in season.