Fry on medium-high heat till onions turn golden brown.
Add powders and fry for another minute.
Make a paste of coriander leaves and red chilly powder in a blender using water. The paste need not be very thick but it should neither be too watery.
:- Remember, red chilly powder is *NOT* reqd, if serrano peppers are used. Quantity of both peppers and chilly powder can be suited to taste and omitted completely the next time if it turns out too spicy the first time.
Add this paste into the above frying ingredients and fry for a couple of minutes.