Salt and pepper ribs, then dredge in flour. Set aside.In a large dutch oven, cook pancetta over medium heat until complete crispy and all fat is rendered. Remove pancetta and set aside. Do not discard grease.Add olive oil to pan with the pancetta grease, and raise heat to high. Brown ribs on all sides, about 45 seconds per side. Remove ribs and set aside. Turn heat to medium.Add onions, carrots, and shallots to pan and cook for 2 minutes. Pour in wine and scrape bottom of pan to release all the flavorful bits of glory. Bring to a boil and cook 2 minutes. Add broth, 1 teaspoon kosher salt, and plenty of freshly ground black pepper. Taste and add more salt if needed. Add ribs to the liquid; they should be almost completely submerged. Add thyme and rosemary sprigs (whole) to the liquid. Put on the lid and place into the oven. Cook at 350 for 2 hours, then reduce heat to 325 and cook for an additional 30 to 45 minutes. Ribs should be fork-tender and falling off the bone. Remove pan from oven and allow to sit for at least 20 minutes, lid on, before serving. At the last minute, skim fat off the top of the liquid. (Can also refrigerate mixture, then remove solid fat from the top.)Serve 2 ribs on bed of creamy polenta, spooning a little juice over the top.