Heat a large Dutch oven over medium-high heat. Add EVOO, the beef and pork; brown and crumble. Season with the chili powder, salt and pepper. Add the carrot, celery, onion, garlic, rosemary, bay leaf and cloves and cook for 8 to 10 minutes to soften the vegetables. Add the tomato paste and stir a minute. Add the beef stock, diced tomatoes and passata or tomato sauce. Simmer to combine the flavors and thicken. Cool and store; reheat over medium heat.
To serve, bring the chicken stock to a boil in a small saucepot, whisk in the polenta, 3 minutes. Stir in the butter, cheese, salt and pepper.