Marinate the chicken: mix the chicken with the beaten yogurt, garlic paste, ginger paste, red chilli powder, salt and coriander powder. Cover and refrigerate for 1 hour.
While the chicken marinates, heat the oil in a large pot. Fry the finely chopped onions on high heat, stirring, until golden brown. Do not over-brown them or the korma will turn bitter. Take them out on a plate and let them cool. Do not grind them yet.
In the same oil, fry the cardamoms, black peppercorns, cloves, bay leaves and cinnamon sticks for a while on high heat, stirring.
Add the marinated chicken. Fry for 10 minutes on high heat, stirring from time to time so it does not stick. Do not add water.
Add the 1 cup yogurt (make sure it is not cold, or lumps will form) and mix well. Cover and cook for 8–10 minutes on medium heat, checking once or twice in between.
Grind the 15 almonds with a little water and add them to the chicken. Cook for 2 minutes.
Now grind the cooled fried onions with a little water and add them to the chicken. Mix well and cook for 2–3 minutes. Add the chopped almonds, if using.
Add the 1 cup water. Cover and cook for 5 minutes on medium heat. Remove the lid and lower the heat so the oil separates.
Grind the fresh spice mix (cloves, black peppercorns, green cardamoms, cinnamon sticks, black cardamoms, cumin seeds and bay leaf) and stir about 1 tablespoon into the korma. Add the kewra water now, only if you like it — she did not add it. Dish out in a serving dish and serve.