Method
Make the paste
Crush half the garlic cloves with a generous pinch of salt into a rough paste. Add the anchovies and crush again until you have something that looks almost uniform — don't worry about it being perfect. Stir in the rosemary, thyme, lemon zest, and olive oil. Taste it. It should be intensely savoury and fragrant. Season with black pepper.
Score and stuff the lamb
Using a small sharp knife, make 20–25 deep incisions all over the shoulder, going about 3 cm deep. Push a halved garlic clove into each slit. Then rub the paste aggressively all over the lamb — into every crevice and under any flaps of fat you can find. Cover and refrigerate overnight, or at minimum 4 hours.
Set up for the long cook
Take the lamb out of the fridge 1 hour before cooking. Heat your oven to 160°C (140°C fan). Place the lamb in a deep roasting tin, pour the wine and stock around (not over) the meat, and cover tightly with two layers of foil. The steam is doing most of the work here.
Roast low and slow
Roast for 5.5–6 hours, until the meat is completely yielding and a skewer meets no resistance. Remove the foil, increase heat to 220°C, and roast for another 25–30 minutes until deeply caramelised and dark in patches. Watch it — you want colour, not char.
Rest, then make the sauce
Transfer the lamb to a board and rest uncovered for 30 minutes. Meanwhile, pour the roasting juices into a small saucepan, skim any obvious fat, and reduce by a third over high heat. Add the vinegar, taste, then whisk in the cold butter off the heat. The sauce should be glossy and deeply savory — don't over-reduce it.
A note on anchovies: Don't skip them. You won't taste fish. You'll taste depth — that impossible richness that makes people ask what your secret is. Tell them it's patience. It's also anchovies.