1. Dry roast each of the ingredients separately until you smell the fresh aroma of the spice and the color changes lightly.
2. Keep aside and let cool.
3. Powder the roasted spices in a blender; DO NOT add any water while powdering.
4. Store in an airtight container.

Tip:
While measuring red chillies, chop them into tiny pieces; this way, it`s a lot easier to stuff into cups and measure them.
While powdering, you might want to powder coriander seeds and dry red chilies separately 'cause, coriander seeds and red chilies take longer to grind.
Rasam powder has a shelf life of about 6 months, so feel free to make enough and store in air tight containers.
You might want to store this masala in the refrigerator to retain its freshness and aroma.

Courtesy: http://maneadige.blogspot.com/