Toast the coriander, cumin, fenugreek, mustard, cinnamon stick, cardamom, chiles, and peppercorns in a dry skillet over medium heat until the spices become fragrant. Make to stir them around the pan or they will burn. Don't inhale the fumes, as they will make you sneeze! When they start to pop, they are done.

Pour into a plate to cool, and add the curry leaves to the skillet. Turn down the heat to low, and lightly toast just until they start to dry out. Transfer to plate to cool.

Transfer the toasted spices and curry leaves to a spice/coffee grinder. Grind until you have a fine powder. Transfer to a bowl and add the turmeric. Mix well. Store for up to 3 months in an airtight container, out of direct sunlight.