The key to a good Qorma is the thorough browning of the onions. The onions must be caramelized to a deep golden-brown, which gives the stew its dark colour and naturally sweet flavour. The meat should be slowly simmered until it is completely tender and falling apart.
Heat the oil in a large pot or cauldron. Sear the meat in batches until golden brown. Remove it from the pot and set aside.
Add the chopped onion to the oil. Sauté over medium heat for 15-20 minutes, stirring occasionally, until the onion darkens to a deep golden-brown/caramel colour. This is crucial for the colour and flavour of the Qorma.
Add the crushed garlic, tomato paste, and all the spices (turmeric, coriander, cumin, Garam Masala, salt, and pepper) to the onion. Stir for 2-3 minutes until the mixture is heated through and the spices become fragrant.
Return the meat to the pot. Add warm water or broth until the meat is almost submerged.
Bring to a boil, then reduce the heat to low, cover, and gently simmer for 1.5 to 2 hours, or until the meat is extremely tender and falling apart.
Stir occasionally and check the liquid level; if it becomes too dry, add a little more water.
Season with salt and pepper to taste. The sauce should be thick. If it is too thin, boil it uncovered over higher heat for 5-10 minutes.
Serve hot, poured over Palau rice (classic Basmati) or with pieces of fresh Naan bread. Garnish with fresh coriander.