Heat oven to 160C/140C fan/gas 3.
Finely chop the rosemary, then mix
with the garlic, capers, anchovies,
olive oil and zest and juice of 1 lemon,
reserving the used lemon halves.
Make 3-4 slashes across the top of
the shoulder, then rub the rosemary
mixture all over the lamb.
Scatter the onion into the base of a
large roasting tin, cut the remaining
lemon in half, squeeze the juices into
the tin, and place all the used lemon
halves in the tin with the onions. Place
the lamb on top and roast for 1 hr.
Pour in the wine and roast for a further
3 hrs until the meat is really tender.
Leave to rest for 15 mins then serve,
pulled into chunks rather than carved,
with any pan juices.