250g/9oz celeriac, peeled
2 tsp chopped fresh mint
350g/9oz floury potatoes, peeled
2 large sprigs fresh rosemary
1 level tbsp plain flour
1 tsp redcurrant jelly
225ml/8fl oz hot beef stock
salt and freshly ground black pepper
dash gravy browning
1 tbsp olive oil
100ml/3陆fl oz port
knob of butter
2 loins of lamb