1 fennel bulb, trimmed and sliced into 8 wedges
4 garlic cloves, finely sliced
1 orange, cut into quarters
1 large red onion, finely sliced
1 rosemary sprig
1 sage sprig
salt and freshly ground black pepper
150g/5½oz peeled and cooked chestnuts, roughly chopped
2 cinnamon sticks
1kg/2lb 4oz lamb shoulder, boneless and rolled
230ml/8¼fl oz dry sherry