Mix 200g of grated paneer, 100g of boiled, grated potato, 2½ tablespoons of cornstarch, 1 teaspoon of grated ginger, 1 chopped green chili, ½ teaspoon of salt, and ½ teaspoon of garam masala. Knead until smooth; shape into small balls.
Heat oil for deep-frying until a pinch of the mixture sizzles and rises. Fry one kofta first; if it breaks apart, knead a little more cornstarch into the mixture. Fry the rest in batches until golden.
Heat 1½ tablespoons of oil in a pan. Add 2 green cardamom pods and 1½ cups of sliced onion and sauté until soft. Stir in 1 tablespoon of ginger-garlic paste.
Add 350g of chopped tomatoes, 18 cashews, and a little salt. Cover and cook for 8 minutes, until mushy.
Stir in ¾ teaspoon of Kashmiri chili powder, ¾ teaspoon of garam masala, and 1 teaspoon of ground coriander; cook over medium-high heat for 3 minutes. Blend with 1 cup of cold water until smooth.
Melt 2 tablespoons of butter in the pan. Add the purée, 1 teaspoon of sugar, and 1½ teaspoons of crushed dried fenugreek leaves, and simmer until slightly thickened.
Stir in ¼ cup of heavy cream. Pour the hot sauce over the koftas to serve.
