1. To make the marinade, pound the garlic, parsley and salt with a mortar and pestle. Mix with the olive oil, lemon juice, zest and pepper. Pour over the lamb and rub thoroughly, then cover with cling film and marinate in the fridge for 30–60 minutes.
2. Preheat the oven or a BBQ with a lid to 180ºC. Place the lamb on a large roasting pan. Saturate the meat with the marinade using a brush, then cook for 40 minutes for a medium result. Cover the meat with foil and rest the meat for 15 minutes before slicing.
3. To make the anchovy cream sauce, combine the garlic and milk in a small saucepan. Cover and simmer very gently until the garlic is soft enough to squash easily between your fingers. Add the anchovies and stir over low heat until dissolved. Add the olive oil and butter and blitz in a blender until smooth. Add the cream and stir to combine. Keep warm.
4. Bring a large pot of salted water to the boil. Add the zucchini and green beans and blanche for about 10 seconds (so they retain a nice crunch). Rinse with cool water and drain in a colander, then transfer to a large salad bowl. Add the garlic, mint, olive oil, lemon juice and zest and toss until mixed through.
5. To serve, slice the lamb and serve on a board. Drizzle some of the anchovy sauce over the lamb and put the remainder in a gravy boat on the side. Leave the zucchini and beans in the bowl with servers for guests to help themselves.
• For the perfect roast every time, use the RoastMate smartphone app. You just enter the cut and weight and it will give you exact timings and temperatures.
• Try switching out the lamb leg for a shoulder or boned and rolled loin roast.