In a sauté pan, dry roast coriander seeds, cumin seeds, pepper separately until it starts crackling or letting out aroma. Ensure to keep it in medium flame.
Transfer those to a wide plate. Add the toor dal to the sauté pan and sauté it until its all begins to turn golden brown color. Transfer to the same plate.
Sauté the chillies and curry leaves (if using) until the curry leaves are crisp and the chillies begin to blacken. Keep moving them around to avoid burning them. Add to the plate and let it all cool down.
Once its cooled down a bit, transfer it to a blender or spice grinder and pulse a few times. After its all broken down, grind it to an almost fine but not completely fine powder. It should be in between coarse and fine.
Transfer it back to the plate and stir with a fork to spread it out. Once it has cooled down, transfer it to an airtight container to store it for later.