Toast the cumin, black mustard, and fenugreek seeds, the split dal, and the fresh curry leaves as described below Add the peppercorns and chili pods and grind the mixture to a fine powder.
Add the coriander and turmeric and mix well.
To toast spices on the stove top, place them in a dry, heavy-bottomed pan and cook them briefly (5 to 7 minutes) over low heat, stirring occasionally, until they darken and begin to release their aromas.
Heated mustard seeds will begin to pop, and may jump out of the pan, so have a lid ready.
Oven toasting takes somewhat longer; spread the ingredients on a dry cookie sheet and place in an oven preheated to 200 F; stir every five minutes or so.
Grind toasted ingredients to a powder with a mortar and pestle, spice grinder, coffee mill (not the same one you use for coffee), or a blender, the pass them through a fine sieve.
Transferred immediately to a glass container and stored away from moisture, light, and heat, toasted and ground spices can maintain their flavor as long as four months.