Idli podi/powder/

 

Dry roast them and grind.

An alternative approach:

For dal powder try this 3 ingredients only - chana dal, zeera and Dry red chillies. Quick and jiffy way for making idli podi - Take 30-50 GM's of roasted chana dal , 1 tablespoon of zeera  and few red chillies around 5-10( depending on ur spice levels)

Dry roast the chana dal and keep them aside, dry roast the zeera and red chilies together and keep them aside. Take care not to burn any of them. Then add a pinch or two pinches of hing to the roasted zeeera and red chillies and turn off the flame. Hing burns quickly so ensure u add hing only after the stove is turned off. Finely grind them and add salt according to ur requirement while grinding. Entire process takes less than 15 min max. Do give it a try ( it's called Kandi podi that's used for idlis and dosa)