Short Ribs Braised with Barolo

Name: Short Ribs Braised with Barolo
Ingredients: 3 lb. beef short ribs; Salt and freshly ground pepper, to taste; 1/2 cup all-purpose flour; 3 oz. pancetta, cut into 1/2-inch pieces; 2 Tbs. olive oil; 1 yellow onion, diced; 1 carrot, peeled and diced; 2 celery stalks, diced; 3 garlic cloves, chopped; 1 1/2 Tbs. tomato paste; 1 bottle (750ml) Barolo or other full-bodied red wine; 1 Tbs. veal or beef demi-glace; 1 fresh rosemary sprig; 1-inch piece Parmigiano-Reggiano cheese rind; Polenta for serving