Add the coriander seeds to a pan and allow to roast on low heat for about a minute and then add the peppercorns, cloves, cardamom, bay leaf and cinnamon.
Roast for another 15 seconds and then add the curry leaves.
Mix regularly and keep the heat low to avoid burning the spices. Continue to roast for another 30 seconds and then add the chillies.
Allow to roast for a minute and finally add the fennel and cumin seeds.
Roast for another 15-30 seconds and remove from heat.
Allow to cool completely and then grind to a fine powder. Store in an airtight container.
Notes
Roasting the spices has to be done in steps as some of the spices need to be roasted longer than the others. Some versions of this blend also use fenugreek, mustard and pandan leaves.