Toast the coriander seeds, cumin seeds, fennel seeds, cardamom pods, cinnamon stick, cloves, and peppercorns in a medium, heavy skillet over medium-low heat for 5 minutes. Transfer the mixture to a spice mill. Add the ginger, nutmeg, aleppo peppers, and salt to the spice mill. Grind until well combined (if necessary, do separate batches in the spice mill).