French in inspiration and classic in appeal, this is a splendid one-pan dish that family and friends will adore
3 tbsp balsamic glaze (available at selected supermarkets and delis)
1 leg lamb (about 2-2.2kg), ideally rare breed or mountain breed
2 x 50g cans salted anchovies in olive oil 14 garlic cloves, skinned and halved lengthways 4 sprigs fresh rosemary, marjoram or flat-leaf parsley, plus extra to garnish 2 large onions, sliced crossways 350g Puy lentils 1 tbsp vegetable-stock granules 2 tbsp extra-virgin olive oil
Step 1) Pre-heat the oven to 220°C, Gas Mark 7. Use half the balsamic glaze to brush over the lamb. Drain the anchovies, keeping the oil. Halve 12 anchovies crossways with scissors. Wrap one anchovy half around a garlic sliver. Cut 1cm into the lamb with the point of a sharp knife. Push in a bit of herb then an anchovy-garlic ‘spike’. Make 23 more spikes and insert each with its herb; 4 garlic bits will be left. Chop these and scissor-snip remaining anchovies into a mortar with the rest of the balsamic glaze. Pound and mash to a rough paste and put to one side.
Step 2) Make a bed of most of the sliced onions in a roasting pan. Drizzle over the anchovy oil. Set the lamb on top. Roast, uncovered, for 30 minutes; reduce oven to 160°C, Gas Mark 3 and cook for an hour. Half an hour before the end of roasting time, put the lentils, remaining onions and 800ml hot water into a deep pan. Boil, reduce to a simmer and cook, part-covered, for 25 minutes until tender; the liquid will reduce. Once cooked, cover the lamb with foil and leave for 10-15 minutes. Drain and discard most of the lentil liquid. Stir the stock into the lentils over the heat until dissolved, then the anchovy paste and olive oil. To serve, spoon the lentils around the roast lamb, garnished with extra rosemary.