Roast Lamb Shoulder Stuffed with Sausage & Spinach

For the stuffing:

• 1 bunch spinach (about 10 oz.), stemmed and washed, excess water still clinging
• 2 links (4 oz. total) sweet Italian sausage, removed from the casings and crumbled
• 1-1/2 cups fresh breadcrumbs
• 1/2 cup grated Pecorino Romano
• 1 large egg

For the lamb:

• One 3- to 3-1/2-lb. boneless lamb shoulder roast
• Kosher salt and freshly ground black pepper
• 1/4 cup olive oil
• 6 heads garlic, top half sliced off
• 8 sprigs fresh thyme

Heat the oven to 450°F.

Make the stuffing:

In a large skillet over high heat, cook the wet spinach until completely wilted (there’s no need to add oil to the pan as long as water droplets are clinging to the leaves). Transfer to a colander and run under cold water to cool; squeeze out the excess water and finely chop. In a large bowl, mix the spinach with the sausage, breadcrumbs, cheese, and egg. Set aside.

Trim, stuff, and roast the lamb:

To trim the lamb shoulder roast, start by trimming off large pockets of fat by making small swipes of the knife to ease the fat loose. Remove thinner pieces of fat by pulling toward you. Angle the knife as close to the meat as possible, cutting away from you. Cut the lamb into an even thickness by butterflying thicker spots, if need be. Cut a sideways incision and open the meat like a book.

Season the top surface of the lamb with salt and pepper. Spread on the stuffing in an even layer, leaving a few inches uncovered at the end. Starting with the bare edge away from you, roll up the roast. With kitchen twine, tie the roast in four or five places to secure a compact cylinder. Trim the extra twine.

Set the roast in a flameproof roasting pan or casserole dish, brush it with the olive oil, and season it with more salt and pepper. Roast for 30 minutes and then lower the heat to 350°F. Rub the cut side of the garlic heads in the pan juices and arrange the garlic (cut side down) around the roast, along with the thyme sprigs. Cover the pan with foil and roast for 1 more hour.

Remove the foil, turn the garlic cut side up and roast uncovered until an instant-read thermometer inserted into the center of the stuffing registers 165°F, another 10 to 15 minutes. Transfer the roast to a cutting board, tent it with foil, and let rest for 5 to 10 minutes. Meanwhile, remove the garlic and thyme from the roasting pan; reserve the garlic and discard the thyme. Tilt the pan and spoon off any fat. To deglaze the pan, add 1/4 cup water, set the pan over low heat, and simmer, scraping the browned bits with a wooden spoon; add more water if needed. Cut the twine and slice the roast in 1/2-inch slices. Spoon the pan sauce over the slices and serve with the roasted garlic.