Clean all the dry spices .Check for any debris or stones in coriander seeds and peppercorns ,if there discard it.
Heat a griddle ,preferable iron griddle or else you can use non stick or anodized skillet too
Dry roast all the ingredients on a low to medium heat ,one by one till you get the pungent smell of each spices.
Take measures ,not to burn or brown the spices.
Turn off the heat and then at last add Jeera /cumin seeds , heat of the iron griddle is sufficient to crackle the jeera seeds.
Once all the ingredients ,cools down . Place it in a dry mixer jar and blend to fine powder.
Store it in any air tight dry glass jar and use it as required.