Skip to main content

Slow-Roast Spiced Lamb Shoulder with Sumac Onions

This slow-roast spiced lamb shoulder is a magnificent centrepiece that fills the kitchen with the warm, aromatic scents of cinnamon, cardamom and nutmeg. By roasting the meat slowly at a low temperature, the lamb becomes incredibly tender while the fat renders down, resulting in a succulent texture that pairs beautifully with the vibrant, zesty garnish. The dish offers a sophisticated balance of rich, melt-in-the-mouth meat and a sharp, citrusy crunch from the marinated onions.

As a diabetes-friendly main course, this recipe focuses on high-quality protein and fresh herbs rather than sugary glazes. The sumac-spiced onions provide a bright acidity that cuts through the richness of the roast without the need for heavy sauces. Serve this alongside steamed seasonal greens or a cauliflower mash for a comforting, healthy Sunday lunch that feels truly indulgent.

Continue reading below

Ingredients for Slow-Roast Spiced Lamb Shoulder with Sumac Onions

  • 1 (6–7-lb.) bone-in lamb shoulder

  • 2 tablespoons black peppercorns

  • 2 tablespoons coriander seeds

  • 2 tablespoons paprika

  • 2 teaspoons ground cinnamon

  • 1 teaspoon ground cardamom

  • 1 teaspoon ground cloves

  • 1 teaspoon freshly grated nutmeg

  • 1 large red onion, thinly sliced

  • 45ml fresh lemon juice

  • 2 teaspoons sumac

  • 1/2 cup mint leaves

  • 1/2 cup parsley leaves with tender stems

  • Kosher salt, freshly ground pepper

  • A spice mill or mortar and pestle

Season lamb very generously with salt and pepper; place on a wire rack set inside a rimmed baking sheet.

Toast peppercorns and coriander seeds in a dry small skillet over medium heat, tossing often, until fragrant, about 3 minutes; let cool. Finely grind in spice mill or with mortar and pestle; transfer to a small bowl. Mix in paprika, cinnamon, cardamom, cloves, and nutmeg, then rub all over lamb. Chill uncovered at least 4 hours and up to 1 day.

Let lamb sit out on counter at room temperature 1 hour before roasting.

Place a rack in middle of oven; preheat to 135°C. Transfer lamb to a roasting pan and pour in 725ml water. Cover tightly with foil and cook, turning lamb over and rotating pan halfway through, until meat is almost falling off the bone, 3–3 1/2 hours. Remove lamb from oven and turn up heat to grill (or to highest heat if you have a drawer-style grill). Discard foil, transfer lamb to a cutting board, and pour off liquid in pan. Return lamb to pan; roast, uncovered, until nicely browned, about 5 minutes.

Meanwhile, toss onion, lemon juice, and sumac in a small bowl with your hands, squeezing onion a bit to soften.

Just before serving, toss mint, parsley, and a pinch of salt into onion mixture. Serve lamb topped with onion salad.

Disclaimer

While every effort has been made to ensure the information is accurate and up to date, individual needs may vary and dietary requirements can differ based on personal health conditions. Always check food labels and allergen information before preparing or consuming any recipe. If you have specific health concerns, allergies, intolerances, or are following a medically prescribed diet, seek advice from your GP, pharmacist, or a registered dietitian before making significant changes to your diet or lifestyle.

Article history

The information on this page is peer reviewed by qualified clinicians.

  • 28 Jan 2026 | Originally published

    Authored by:

    UK recipe editors

    Peer reviewed by

    UK recipe editors
flu eligibility checker

Ask, share, connect.

Browse discussions, ask questions, and share experiences across hundreds of health topics.

symptom checker

Feeling unwell?

Assess your symptoms online for free

Sign up to the Patient newsletter

Your weekly dose of clear, trustworthy health advice - written to help you feel informed, confident and in control.

Please enter a valid email address

By subscribing you accept our Privacy Policy. You can unsubscribe at any time. We never sell your data.