Add the remaining 2 1/2 tablespoons of olive oil to the casserole. Add the turkey, season with salt and pepper and cook, stirring to break up the meat, until nearly cooked but still slightly pink, about 4 minutes. Add the chile powder and cumin and cook until the liquid evaporates, about 5 minutes longer. Add the tomato sauce, water, thyme, chipotles, cornmeal, bay leaves, oregano and cooked vegetables and bring to a boil. Partially cover and cook over moderately low heat, stirring occasionally, until the sauce is slightly reduced and the meat is tender, about 45 minutes. Add the beans, season with salt and pepper and simmer 10 minutes longer. Serve in deep bowls, passing the cheese, cilantro, sour cream and tortillas on the side.