In a frying pan over medium heat, add the cumin seeds, coriander seeds, black peppercorns, cardamom pods, cloves, and cinnamon sticks.
Toast the spices for about 3-5 minutes until fragrant, stirring frequently to prevent burning.
Once toasted, remove from heat and allow the spices to cool for a few minutes.
Transfer the roasted spices to a spice grinder or mortar and pestle. Add the grated nutmeg if using fresh.
Grind the spices into a fine powder, making sure there are no large pieces left.
Store your garam masala in an airtight jar in a cool, dry place.
You can adjust the spices according to your preference. Some variations may include dried bay leaves or dried red chilies for extra heat.
For best flavor, use the garam masala within a month, though it can last several months when stored properly.