1 cup (¾ oz) loosely packed flat-leaf parsley leaves
1 tbsp fresh thyme leaves
6 cloves garlic
1 tsp ground cumin
⅓ cup (2¾ fl oz) olive oil
divided
1 tbsp finely grated lemon zest
1 tbsp finely grated orange zest
1 tbsp fresh lemon juice
1 tbsp whole grain mustard
1 tbsp (¾ oz) honey
3½ lb boneless leg of lamb or lamb shoulder
fat trimmed and butterflied
Flaky sea salt
to season
Freshly ground black pepper
to season
1 lemon
halved
To serve
Watercress
Instructions
1Combine the rosemary, parsley, thyme, garlic, cumin, ¼ cup (2 fl oz) olive oil, lemon zest, orange zest and lemon juice in the small bowl of a food processor. Process to a coarse puree. Spoon the puree into a bowl and set aside.
2Combine the mustard, honey and remaining oil in a small bowl and mix well.
3Unroll the lamb and place fat side down between 2 pieces of plastic wrap. Make a few shallow cuts in the thicker portions of the lamb, this will help it to flatten more easily when pounding. Pound the lamb using a rolling pin or meat mallet to about ¾ inch thick, creating a rectangular shape.
4Season both sides of the lamb with salt and pepper, then place the lamb on a board fat side down. Spread the herb and citrus puree evenly over the lamb.
5Starting from a short side, tightly roll the lamb. Using kitchen twine, tie at 1 inch intervals to secure the lamb and create a round shape.
6Put the lamb in the roasting pan. Brush all over with the mustard mixture. Put the lemon, cut side down in the pan.
7Insert the wire rack in the bottom shelf position. Preheat the oven. Select ROAST/325°F/65 minutes.
8Once preheated, put the lamb in the oven and cook for 65 minutes for medium-rare.
9Transfer the lamb to a plate, cover loosely with foil and set aside to rest for 20 minutes.
10Arrange the watercress on a serving platter, top with the lamb and roasted lemon. Slice and serve.