Prepare: peel and thinly slice the 2 Spanish onions and chop the 3 medium tomatoes. Measure out the whole spices (1 inch cinnamon, 3 pods green cardamom, 3 pieces bay leaves, 9 cloves) and set aside the 1 teaspoon mace powder for later.
Heat 100 ml sunflower oil in a heavy casserole or deep pan over low–medium heat until warm but not smoking.
Add the whole spices (cinnamon, green cardamom, bay leaves, cloves) to the hot oil. Fry, stirring occasionally, until the spices become fragrant (about 1–2 minutes). Do not add the mace yet.
Add the sliced onions to the pan. Cook, stirring regularly, until the onions are golden brown (about 8–12 minutes). Adjust heat as needed to prevent burning.
Add 1/2 tablespoon garlic paste and cook for 1 minute, stirring so it does not stick.
Add 1.5 tablespoons ginger paste plus the powdered spices: 1/2 teaspoon turmeric, 1 teaspoon chili powder, and 1 teaspoon coriander powder. Cook and stir for about 2 minutes, sprinkling 1 tablespoon water once if the spices start to stick, to prevent burning.
Add the chopped tomatoes. Cook, stirring occasionally, until the tomatoes break down and you see oil separating around the edges of the mixture (about 5–10 minutes).
Add the 1.5 kg goat meat with bone to the pan. Stir well to coat the meat in the spice-onion-tomato mixture, and continue to stir for about 5 minutes until the meat begins to release its juices.
Pour in 1 litre water, bring to a gentle simmer, reduce the heat to low–medium, cover partially, and cook for 1½ hours, or until the goat is tender. Stir occasionally.
Check the sauce consistency; if it is too thin, simmer uncovered over low heat until it reaches the desired thickness.
Stir in 4 sprigs of coriander leaves and the reserved 1 teaspoon mace powder, then remove the pan from the heat.
Garnish with the remaining 1 sprig of coriander leaves before serving.
Tip: Slow, gentle cooking will help ensure the meat becomes tender.