In a large mixing bowl, add the mutton mince, 1 onion, garlic paste, turmeric powder, 1/2 tsp red chili powder, 1/2 garam masala powder, 1 egg, and besan. Mix thoroughly or put it in the food processor till thoroughly mixed. Keep it refrigerated for at least 30 minutes.
Now take a ball of this keema and wrap it over the hard boiled egg. Do this for all the eggs and deep fry in hot oil till dark brown in color. (Do a kofta test in hot oil first, drop a small ball of the keema dough, if it falls apart in the oil, coat the koftas in egg and fry.)
Heat 2 tbsp oil in a kadai and add onion and fry till light golden. Then add, green chili, ginger and garlic paste. Fry for another minute till the raw smell from the ginger garlic paste vanishes.
Now add red chilly powder, coriander powder, garam masala powder and salt. Put 1/4 cup of water so that the masala mixes well.
Add tomato paste and let it simmer on medium heat for 8 - 10 mins or till oil separates.
Add the fried koftas and the cashew nut paste with a cup of water and simmer for couple of minutes.
Garnish with coriander leaves and serve hot.