Heat a dry frying pan over a medium heat, Add the coriander seeds first and toast for 2-3 mins shaking the pan frequently, until they turn a deep, dark woody brown. Transfer to a plate to cool.
In the same pan, add the cumin and fennel seeds. Toast for 2 to 3 minutes until they become intensely aromatic and slightly darkened. Remove from the pan and add to the cooling plate.
Add the rice, peppercorns, mustard seeds, and fenugreek seeds to the pan. Toast for 2 to 3 minutes until the rice turns a light golden colour. Watch closely so the fenugreek does not turn black or bitter. Transfer to the plate.
Add the cloves, green cardamom seeds, and fresh curry leaves to the pan last. Toast for 1 to 2 minutes until the curry leaves become completely dry and brittle. Remove from the heat.
Allow all the toasted ingredients to cool completely. Transfer the mixture to a spice grinder or a mortar and pestle, and grind until it forms a fine, uniform powder.
Store in a sealed jar.