This is a Maharashtrian easy and quick to cook side dish, that goes well with Indian breads and rice.
In a bowl using a wire whisk beat together the gram flour, buttermilk and curd to create a lump free watery batter. Keep aside
Finely chop onion, green chilli, garlic and tomato. Keep aside
In a heavy bottomed pan heat oil and add the mustard seeds. After the mustard seeds splutter, add asafoetida and curry leaves. Fry for 5 -10 seconds
Add the chopped garlic, green chilli and onion. Sprinkle a pinch of salt to allow the onion to cook faster.
Once the onion turns translucent and is cooked through add turmeric powder, chilli powder and salt. Sauté for a minute.
Add the chopped tomato and cook until soft.
Pour in the gram flour, buttermilk and curd mixture. Add water and cook on low heat for 10-15 minutes to allow the gram flour to cook completely. Stir every 2-3 minutes
Khatta besan is ready when the mixture thickens to a thick cake batter consistency.