Heat oil in nonstick vessel, add mustard when oil is hot then cumin. Add crushed garlic and turmeric, fry for 1/2 min, now add chillies and fry for 1/2 min.
After this add cut capsicum and fry till soft.
Now add buttermilk and let it boil when boiling sprinkle besan (add besan till it is thick mixture) with one hand and mix with other hand (with spatula), now add salt, coriander and mix then cover and steam for 4-5 min.
If sticking add little more oil and steam if again sticking add some more oil.when done let it cool for a while and crumble with hand (it is very imp to crumble).
Serve with rice or chapati.