In a saucepan over medium heat, add the coriander seeds and curry leaves. Heat the spices, stirring often, until aromatic - 30 seconds to 1 minute, then transfer the spices to a bowl.
In the pan, add the toor dal and chana dal and heat, stirring often, until they turn a light brown. Transfer the mix to the plate with the coriander and curry leaves.
Place the black peppercorns and cumin seeds in the same pan and heat, stirring often, both until aromatic - 30 seconds to 1 minute, then transfer to the plate with other spices.
Add the Kashmiri chilies (or dried red chili of your choice) to the pan and heat them, stirring often, until aromatic.
Place all ingredients into a spice grinder (or use a mortar and pestle) and grind the spices into a fine powder. Use immediately, or place into an airtight jar for future use.