Make the most of new-season lamb with a classic combination: fragrant herbs, sweet root veg and slow-cooked meat.
1 x 2.25kg shoulder of lamb, see method
Sea salt and black pepper
For the herb crust
15g fresh mint leaves
15g fresh rosemary sprigs
120g fresh white breadcrumbs
1 tsp dijon mustard
1 tsp balsamic vinegar
For the roasting pan
2 cloves garlic
A few sprigs of rosemary
Rub the lamb all over with olive oil, and season it well. Have a roasting tray at the ready that will hold the lamb snugly.
Next make the crust by finely chopping the mint and rosemary by hand, and placing together in a large bowl. Whiz the remaining crust ingredients in a food processor with 3tbsp oil, then combine with the chopped herbs and set aside.
Preheat the oven to 210°C/fan 190°C/gas mark 6¹∕2.
Cut the onions, beetroot and whole garlic in half and arrange in the centre of the roasting tray. Add the carrots, whole, and drizzle a little olive oil over the trayful of ingredients. Place the lamb on top, fat side up; season again and add an extra drizzle of oil.
Pour water into the roasting tin to a depth of 1cm. Place the tin in the oven and roast for 65 minutes, basting every half hour, adding a little more water as necessary to prevent the tin from drying out and smoking.
Remove the roasting tin from the oven and, using your hands, press the crust mixture evenly over the surface of the joint. Add the sprigs of rosemary to the tin. Drizzle over a little more oil, then return the lamb to the oven and continue roasting for 25-30 minutes (or until done to your liking). Transfer the lamb to a carving plate, loosely cover with foil and leave to rest in a warm place for 20-25 minutes.
For a different sized lamb joint, calculate the cooking times at 33 minutes per kg plus an additional 15 minutes (for example, a 2.5kg joint will take 1 hour 38 minutes). Baste every 30 minutes and add the crust 25-30 minutes before the end of cooking time.