Heat oil in a saucepan. Add the cardamom, cloves and cinnamon
Add the onions and saute until the onions are soft and just beginning to turn color.
Add the ginger and garlic, saute for no more than 30 seconds, then add in the turmeric, cayenne and coriander powders. Stir to mix.
Add the tomatoes and cook until the tomatoes are pulpy and broken down, then add in the cashew nuts, pumpkin seeds and kasoori methi and mix well. Turn off the heat.
Remove the entire mixture to the blender, add two cups of cold water and process to a really smooth paste.
This step is optional, but you can strain the sauce at this point for a really smooth texture.
Add the sauce back to the pan and bring it back to a boil over low heat. If it's too thick to your liking, dilute with more water. Mix in the garam masala and add salt. Stir in the sugar if using, and turn off the heat.
Pour the hot sauce over the kofta balls, and serve immediately.