Marjoram is a perennial plant that is very closely related to oregano. The flavor is warm, spicy, herbal, and a tad bitter the way oregano is, but a bit sweeter with a mystery of mint to it. Used throughout Mediterranean and Italian cooking, its persnickety oils don’t make it a good candidate for prolonged cooking methods. Sweet marjoram spice should always be added at the very end of cooking to ensure the flavor is at its strongest. Dried marjoram has a stronger flavor than fresh and is usually preferred for this reason.