Tortilla soup has a place, I feel, in practically every collection of Mexican recipes,” says Rick Bayless. This is a vegetarian version of this classic soup, usually made with chicken. Earthy pasilla chile flavors the soul satisfying broth. Pasilla chiles, sometimes called negro chiles, are medium-hot dried peppers with a flavor that defines tortilla soup in central Mexico. Find them and other dried chiles in the produce section of large supermarkets or online. Recipe adapted from Rick Bayless via Eating Well magazine.