2 medium onions
Put the onions and ginger in a blender or food processor and process into a smooth paste (consistency of apple sauce). Heat the butter or oil in a heavy, deep skillet and gently brown the onion-ginger mixture, stirring often. Add the chicken and yogurt. Combine well and cook over medium heat until the mixture becomes rather dry and the chicken begins to brown. Grind the almonds, walnuts and melon seeds until quite fine. Stir them into the milk, then add the mixture to the chicken along with the garam masala, turmeric, chili peppers, salt and ground cayenne. Cook over medium heat, stirring often, until the chicken is very tender and the sauce is very thick (about 10-15 minutes). Stir in the saffron/milk mixture and cook 1-2 minutes longer.