Spicy Braised Short Ribs with Polenta

Name: Spicy Braised Short Ribs with Polenta
Ingredients: 3 tablespoons olive oil; 6 beef short ribs (about 4 pounds); Kosher salt and freshly ground black pepper; 1 pound cremini mushrooms, sliced; 4 cloves garlic, chopped; 1 medium carrot, diced; 1 medium onion, diced; 1 sprig fresh rosemary; 2 cups dry red wine; One 24-ounce jar arrabbiata sauce; Crushed red pepper, as desired, optional; 1/4 cup chopped fresh parsley; 6 cups low-sodium chicken broth or water; 1 1/2 cups stone-ground cornmeal; Kosher salt; 1/2 cup freshly grated Parmesan; 3 tablespoons unsalted butter