750g/1lb 10oz Jersey Royal potatoes, or new potatoes if in season
1 head garlic, cut in half
2 large sprigs mint
1 bunch mint, finely chopped
2 red onions, thinly sliced
4 sprigs rosemary, snipped into 2.5cm/1in lengths
200ml//7fl oz lamb gravy, warmed through
salt and freshly ground black pepper
20²µ/¾´Ç³ú caster sugar
2 tbsp olive oil
100ml/3½fl oz white wine vinegar
2.5kg/5lb shoulder of lamb