Preheat the oven to 325 degrees.

Place a Dutch oven on the stove over medium heat. Add the oil and heat for 2 minutes.

Season the short ribs with salt and pepper and add to the oil. Cook ribs until they are browned on all sides. Remove from the Dutch oven and place in a large bowl.

Add the carrots, celery, onion, and shallots to the Dutch oven. Cook over medium heat, stirring occasionally, until vegetables are softened, about 10 minutes.

Prepare the bouquet garni: place the bay leaf, rosemary, thyme, and parsley in the center of cheesecloth. Bring edges together and tie with kitchen string. Set aside.

Add the flour and the tomato paste to the Dutch oven. Stir to combine. Add half of the merlot and stir with a wooden spoon until all browned bits have been scraped from the pan. Add the remaining red wine and simmer until the liquid is reduced by half.

Stir in the garlic, crushed tomatoes, oregano, and beef stock. Add the bouquet garni.

Return the short ribs to the Dutch oven. Bring the liquid to a simmer. Cover and place in the oven. Cook for 2 1/2 hours or until the short ribs are tender.

Remove the cooked ribs from the Dutch oven. Set the Dutch oven on the stove top over medium heat and simmer to thicken the sauce.

As soon as the short ribs are cool enough to handle, shred into small pieces.

Degrease the sauce and remove the bouquet garni. Return the meat to the pot and simmer until the sauce reduces by half.

Cook the rigatoni according to the package directions. Drain pasta. Serve the rigatoni in bowls topped with the short rib ragu. Sprinkle with parsley and Pecorino Romano.