Garam masala is a mixture of spices from northern India. It contains cumin and coriander seeds, peppercorns, cardamom, cloves, mace, cinnamon and bay leaves. Everything is dry roasted in a skillet until the spices begin to emit their fragrance. It is then cooled and ground in a spice grinder. You could substitute garam masala by curry powder, which is also a spice blend, more or less spicy. You can find garam masala in specialty and Asian grocery stores.