Preparation Char chilies over gas flame or in broiler until blackened on all sides. Enclose in paper bag; let stand 10 minutes. Peel and seed chilies. Cut into 1-inch pieces. Place pork in large bowl. Sprinkle with salt and pepper. Add flour and toss to coat. Heat 4 tablespoons oil in heavy large wide pot over high heat. Working in batches and adding more oil as needed, cook pork until brown on all sides, about 6 minutes per batch. Using slotted spoon, transfer pork to large bowl. Reduce heat to medium. Add onions to same pot and stir until tender, about 6 minutes. Add garlic, oregano and cumin; stir 2 minutes. Return pork and any accumulated juices to pot; add stock, chilies and tomatoes with juices and bring to boil. Reduce heat and simmer uncovered until chili thickens and meat is very tender, stirring occasionally, about 2 hours. Season to taste with salt and pepper. *Fresh green chilies, often called pasillas, are available at Latin American markets.
Preparation Char chilies over gas flame or in broiler until blackened on all sides. Enclose in paper bag; let stand 10 minutes. Peel and seed chilies. Cut into 1-inch pieces. Place pork in large bowl. Sprinkle with salt and pepper. Add flour and toss to coat. Heat 4 tablespoons oil in heavy large wide pot over high heat. Working in batches and adding more oil as needed, cook pork until brown on all sides, about 6 minutes per batch. Using slotted spoon, transfer pork to large bowl. Reduce heat to medium. Add onions to same pot and stir until tender, about 6 minutes. Add garlic, oregano and cumin; stir 2 minutes. Return pork and any accumulated juices to pot; add stock, chilies and tomatoes with juices and bring to boil. Reduce heat and simmer uncovered until chili thickens and meat is very tender, stirring occasionally, about 2 hours. Season to taste with salt and pepper. *Fresh green chilies, often called pasillas, are available at Latin American markets.