1 head garlic, peeled and chopped
1 onion, sliced
1kg/2lb 4oz potatoes, cut into matchsticks
2 sprigs rosemary, broken into small pieces
150g/5½oz Swedish anchovies, chopped
400ml/14fl oz gravy, to serve
salt and freshly ground black pepper
50g/1¾oz fresh white breadcrumbs
75g/2½oz unsalted butter
500ml/18fl oz double cream
1 lamb shoulder