Combine the marinade spices with a pinch of salt in a bowl. Rub the mixture thoroughly over 1000 g lamb, cover, and leave to marinate in the refrigerator for 3–4 hours.
Warm 30 g of the vegetable oil in a wide, heavy pan over medium heat. Tip in the whole spices for the paste and fry for 2 minutes until fragrant. Stir in 300 g onion and cook for 4 minutes until pale golden.
Tumble in 400 g coconut and 480 g tomato with a generous pinch of salt. Fry for roughly 5 minutes until the moisture evaporates, then remove from the heat to cool completely.
Transfer the cooled coconut and tomato mixture into a blender or food processor and grind to a smooth paste.
Heat the remaining 198 g vegetable oil in a deep, heavy pot over medium heat. Fry 600 g potato for 10 minutes until evenly browned, then lift out with a slotted spoon and set aside.
Place the marinated lamb into the hot oil and sear for 5 minutes until browned on all sides. Stir in the blended masala paste, add salt to taste, and pour in 500 ml hot water.
Bring the sauce to a boil, then cover with a tight-fitting lid, turn the heat to low, and simmer gently for 1–1½ hours, stirring occasionally and adding extra water if the gravy reduces too much, until the lamb is fully tender.
Stir the fried potatoes into the curry and simmer for 5 minutes longer. Scatter over 15 g coriander leaf and serve hot.
Use 1 g ground for 4 g whole (or 1 small pinch per 2 to 3 whole cloves). Add with spice powders; disperses intense warmth quickly, so use with restraint.
Allspice berries
Use 100% of the weight whole in tempering. Imparts a warm, clove-like aromatic profile combined with hints of nutmeg and cinnamon.
Use 80% of the weight, finely shredded and browned slowly with a pinch of asafoetida. Replicates the bulk and natural sweetness in gravies without allium.
Use 40% to 50% of the fresh tomato weight mixed with a splash of water. Imparts a deeper red colour, thicker sauce, and slightly sweeter cooked flavour.
Steep a tiny pinch (0.1 g per 2 g turmeric) in 2 tbsp warm water; use to match the rich golden hue. Contributes an aristocratic, honeyed floral flavour rather than earthy bitterness.