zest and juice of 1 lemon, plus 2 extra lemons to serve
2 large bunches rosemary
2.5kg lamb leg
200ml lamb stock (from a cube is fine)
Rub the mixture all over the lamb and leave to marinate for 1 hour.
Finely crush 2 garlic cloves and scrape into a small bowl. Add 30ml olive oil, 1 tbsp finely grated zest, the lemon juice and 2 tbsp chopped rosemary. Season and mix well.
Preheat the oven to 190°C, gas mark 5. Pick several sprigs of rosemary. Use a sharp-pointed knife to make several small incisions all over the meat. Push a sprig of rosemary or garlic clove into each one, then season generously all over.
Scatter 6-8 sprigs of rosemary and the remaining garlic over the base of a roasting tin. Pour in the stock and sit the lamb on top. Roast in the oven for 1 hour 45 minutes for medium. Every 30 minutes or so, remove the lamb from the oven and use a large sprig of rosemary to baste the meat with the liquid in the tin.
Remove the lamb from the oven, cover with foil and leave to rest in a warm place for at least 15 minutes.
Slice the extra lemons in half. Heat the remaining oil in a frying or griddle pan over a high heat. Add the lemon halves, cut-side down, and cook for 2-3 minutes until nicely charred.
Arrange the lamb leg, lemon halves and remaining rosemary on a wooden board, and carve the meat at the table.