Coat the sliced arbi with some rice flour and a pinch of salt. Shallow fry them in 2 tbsp. oil till light golden in colour. Drain and keep aside.
Grind the greens, garlic and chilies to a smooth paste. Blend the buttermilk with salt, turmeric powder, remaining rice flour and coriander-cumin powder. Keep aside.
Heat remaining oil in a pan. Temper with cumin seeds & asafoetida. Saute for a few seconds.
Add the ground paste and saute till dry.
Add the spiced buttermilk & simmer on a low flame till it is slightly thick.
Add the fried arbi and continue to simmer for some more time till you get the desired consistency.
Serve with plain steamed rice or any Indian bread.
