Preheat oven to 375 degrees. On a cookie sheet, coat tomatoes and root vegetables with oil and bake until browned; remove and add to chili mixture.
In a large stock pot, heat oil. Add the diced onions and all peppers; sauté until tender. Add the garlic, chili powder and ground cumin; heat for two minutes then add remaining ingredients. Bring to a boil, then simmer on low for two hours.