Clean the mutton and cut into medium pieces. Heat oil in a pan and add bay leaves, cloves, cinnamon stick and ginger garlic paste. Add the mutton and fry for 2 to 3 minutes. Now add red chilli powder, coriander powder, turmeric powder, yogurt, garam masala and fry until the oil separates. Add the nutmeg, cardamom, spice masala and 3 cups of water and cook on low heat for 3 to 4 hours. Finally, add the flour and cook for about 10 minutes. Garnish with coriander leaves, ginger, onions and green chillies. You can serve mutton nihari with chappati, naan or rice.