Sambar powder is the quintessential spice mix you will find in most South Indian homes. This aromatic spice blend transforms ordinary lentil-vegetable dishes into delicious, wholesome stews called sambar that is often served along with rice, idli or dosa.
In a pan kept over medium-low heat, add oil and once it heats up, add byadgi chilies and fry them till they are aromatic (approximately 50-60 seconds). Remove the chilies and set them aside on a plate to cool.
Add methi seeds, fry them for 10 seconds or so before adding channa dal, urad dal, coriander seeds, mustard seeds, and peppercorns. Fry them till they turn aromatic.
Add cumin seeds and curry leaves. Fry them for another 10-15 seconds and turn off the gas.
Take the pan off the heat and let it cool down for 15-20 minutes before grinding them to a fine powder along with the byadgi chilies.
If the mixture is warm after being ground, transfer it to a plate and once it cools down, transfer the powder to an air-tight container and store it in a cool place. Stores well for 2-3 months.
Notes
Variations - Some folks add hing (asafoetida) and turmeric powder while making Sambar masala while I prefer adding it when I am making sambar.