Chipotle peppers are jalapeno chilies that have been smoked and dried. Their smoky heat is delicious brushed over tortillas and pizzas, and carefully added to soup and stews. A little will go a long way. The puree will keep almost indefinately; if you know you'll be storing it a long time, cover the puree with a thin layer of oil. Enjoy! Adapted from Field of Greens restaruant cookbook.