In a dry skillet, toast the cumin seeds, coriander seeds, fennel seeds, and black peppercorns over medium heat until fragrant, stirring constantly to prevent burning.
Remove the skillet from the heat and transfer the toasted spices to a spice grinder or mortar and pestle. Grind the spices until they are finely ground.
In the same skillet, toast the cinnamon stick, cardamom pods, cloves, and dried bay leaves over medium heat until fragrant, stirring constantly to prevent burning.
Remove the skillet from the heat and add the ground spices, ground turmeric, and ground nutmeg to the skillet. Stir well to combine.
Transfer the mixture to an airtight container, such as a small jar, and store in a cool, dry place until ready to use.