This dish is a real show stopper: a proper roast always impresses, but the two different sauces ensures that no two bites ever gives the same taste!
Preheat the oven to 220°C.
Season the leg of lamb with salt and pepper. Drizzle with the sunflower oil, and rub all sides of the leg of lamb.
Place in a roasting tray and leave to roast for twenty minutes.
When the time is up, lower the oven to 190'C, and leave for another hour.
The new potatoes can go in the oven at this point.
Break up the garlic cloves, but do not peel.
Toss the potatoes with olive oil, salt, pepper and unpeeled garlic, and roast on their own. Or they can go in the same roasting tray as the lamb, and omit the olive oil.
Allow the meat to rest for at least 20 minutes, under a foil tent, before carving.
Pick all the herbs.
Puree the herbs in a mortar and pestle or in a food processor, along with the anchovies, the mustard and the olive oil.
Taste for seasoning, and adjust accordingly.
Set aside until needed.
Break up the garlic heads, but leave the cloves unpeeled.
Top and tail the lemons, and cut into quarters. Remove any pips.
Pick the leaves off te rosemary and thyme sprigs.
Toss everything together and wrap in baking paper, then a layer of tin foil.
Place in the oven along with the lamb, and leave to roast for about 45 minutes to an hour.
While the lamb is resting, empty the content of the foil packets, and roughly chop with a knife or in a food processor.
Stir in the olive oil, and balance the acidity with a few pinches of salt.
Bring a large pot of salted water up to the boil.
Remove the woody stalks from the cavolo nero. Roughly chop into smaller, more manageable chunks, and wash.
Trim the purple broccoli stems.
Blanch both greens separately in the boiling water. They should take about 5 minutes each.
Rince under cold, running water until chilled to stop the cooking. Reserve until ready to serve.
To serve: melt half the butter in a saute pan, and toss in the broccoli until heated through. Plate up. Use the same pan to saute the cavolo nero.
The lamb leg can be carved at the table for a real show, but every other element should be served in their own dish or sauce boat.
Encourage everyone to try both sauces separately, and then combined for more effect.
«If you cannot find cavolo nero, use kale or savoy cabbage instead. For a vegetarian alternative to the leg of lamb, you can serve roasted butternut squash, or beetroots.»