Prepare the Mutton:

• Trim most of the fat from the mutton shoulder, leaving a thin layer, then score the fat.
• Toast the cumin, coriander, allspice, and peppercorns in a dry pan until fragrant.
• Transfer to a blender and add brown sugar, salt, preserved lemons, paprika, cider vinegar, and ½ red onion. Blend into a paste.
• Rub the paste all over the mutton, pressing it into all crevices. Let sit for 30 minutes.

Roast the Mutton:

• Preheat the oven to 200°C fan/gas 7.
• Place the mutton in a large roasting tin and roast uncovered for 40 minutes.

Prepare the Potatoes & Vegetables:

• While the mutton roasts, peel and finely slice the remaining 1½ onions and potatoes.
• Remove the mutton from the roasting tin and set it aside.
• Drizzle the tin with vegetable oil and add the potatoes, sliced fennel, sliced onions, fennel seeds, ground black pepper, and a generous pinch of salt.
• Pour in the chicken stock, then place the mutton back on top.

Slow Cook the Mutton:

• Cover with foil and reduce the heat to 140°C fan/gas 3.
• Cook for 4 hours, allowing the flavors to meld and the meat to tenderize.

Crisp the Potatoes:

• Remove the foil and lift the mutton onto a plate to rest.
• Increase the oven temperature to 200°C fan/gas 7 and return the potato dish to the oven.
• Bake uncovered for 20 minutes until the potatoes turn golden and crisp.

Rest & Serve:

• Remove the potatoes and let them rest, loosely covered with foil, for 20 minutes.
• Serve the potatoes underneath or alongside the mutton, with your choice of peas, broccoli, or greens.