1. Sprinkle ribs with salt and pepper. Heat a large Dutch oven over medium-high heat. Add 1 teaspoon olive oil to pan. Add 8 ribs, and sauté for 6 minutes, turning to brown on all sides. Remove ribs. Repeat procedure with remaining 1 teaspoon oil and 8 ribs. Add onion and the next 5 ingredients (through rosemary) to pan; sauté 3 minutes, stirring constantly. Add wine to pan, and bring to a boil, scraping pan to loosen browned bits. Cook for 13 minutes or until reduced to 2 cups.
2. Preheat oven to 350°.
3. Add broth to pan, and bring to a boil. Return ribs to pan. Cover and bake at 350° for 1 1/2 hours, turning ribs after 45 minutes. Remove ribs from pan, and strain cooking liquid through a fine-mesh sieve over a bowl. Discard the solids. Skim fat; discard. Return cooking liquid to pan. Combine flour and 2 teaspoons water in a small bowl, stirring well. Add to pan, and bring to a boil. Cook for 11 minutes or until reduced to about 1 cup. Stir in vinegar.
4. To prepare gremolata, combine 1/3 cup parsley, 1/2 teaspoon lemon rind, and minced garlic.
5. To prepare polenta, bring 3 cups milk, 1 cup water, 5/8 teaspoon salt, and 1/8 teaspoon black pepper to a boil over medium heat. Slowly stir in 1 cup polenta. Cook 5 minutes or until thick, stirring frequently. Stir in cheese. Place 1/2 cup polenta in each of 8 shallow bowls, and top each serving with 2 ribs, 2 tablespoons sauce, and about 2 teaspoons gremolata.