Mix pakora ingredients (besan, cumin seeds, onions, green chilli, ginger, turmeric, garam masala, red chilli powder, fennel seed, and salt) in a bowl until smooth. Add enough water to make a very thick batter.
Fry mixture by tablespoonfuls in hot oil until golden and crispy, then drain on paper toweling. Keep warm in low oven.
Prepare the kadai sauce:
Blend yogurt, 4 cups water, pinch of turmeric powder, salt, pinch of red chilli powder, and besan. It should look like a buttermilk lassi mixture with besan in it.
Keep it aside for half an hour before starting to make kadi.
For the Remainder of the Kadai:
Pour mustard oil in a big pan (or wok) and heat it until it gets hot. Add cumin seeds mustard seeds, fenugreek seeds, coriander seeds, cloves and let them pop.
Add curry leaves and dry red chilli to the frying mixture.
Add onions and fry until golden brown.
Add the garlic, and ginger to it and fry for 3 minutes, watching that it should not stick to the bottom of the pan.
Add chopped tomatoes and fry for 3-4 minutes.
Add tamarind paste to the pan and let it come to the boil for 4-5 minutes.
Add turmeric powder , garam masala, red chilli powder, salt and fry until oil starts floating on the top and it gives out dark reddish brownish color.
Add the kadi sauce mixture.
Gently stir the curry, as it will start sticking to the bottom. Keep it on medium heat first, and let it come to a boil. Keep watching it and stirring. Simmer for 3-5 minutes, then lower the heat and let it cook on low flame for 20 minutes, stirring occasionally.
Stir for another 5 minutes and check if its thick enough and looks dark yellow. Again stir it for 5 minutes and sprinkle dry fenugreek leaves on it and let it boil for another 2 minutes and than add the pakoras in the kadi.
Boil more for 3 minutes and don’t stir too much as the pakora can break apart.
For garnishing, sprinkle cilantro and serve hot with rice.