1. Preheat oven to 275 degrees. Place a 5-quart flameproof casserole or Dutch oven over medium heat. Add vegetable oil, and heat until it is very hot but not yet smoking. Sprinkle short ribs generously with salt and pepper. Working in batches if necessary to keep the short ribs from touching at all during this crucial browning step, add short ribs to the hot oil (they should sizzle the moment they hit the pan). Cook ribs until well browned, about 10 to 15 minutes. Reduce heat to medium-low if necessary to keep the ribs from overbrowning; do not rush this step. Remove ribs from casserole, and transfer to a large bowl. Set aside.

2. Meanwhile, prepare bouquet garni: Place bay leaf, rosemary, thyme, and parsley in the center of a square of cheesecloth. Bring edges together, and tie with kitchen string. Set bouquet garni aside.

3. Add carrots, celery, onion, and shallots to oil in the casserole, and cook over medium heat, stirring occasionally, until vegetables are softened and golden, about 10 minutes.

4. Add flour and tomato paste to the casserole, and stir to combine. Deglaze the pan: Add ruby port; stir with wooden spoon until all browned bits have been scraped from the pan and the bottom of the casserole is clean. Add red wine, and simmer until the liquid is reduced by a third, 10 to 12 minutes. Add garlic, beef stock, and the reserved bouquet garni.

5. Return browned ribs to the casserole. Bring the liquid to a simmer over medium-high heat. Cover the casserole, and place it in the oven. Cook until ribs are very tender, about 3 1/2 hours.

6. Remove the cooked ribs from the casserole. Set the casserole on the stove top over medium heat, and simmer to thicken sauce just slightly. As soon as the short ribs are cool enough to handle, remove the meat from the bones, and shred into small pieces. (If you like, you can leave the meat on the bone for serving, too.) Discard any fat not rendered during cooking, and discard the bouquet garni. Return shredded meat to casserole, and simmer to reduce sauce by about half, until sauce is of desired ragu consistency, about 10 minutes.

7. Fill a large pot with water. Set over high heat, and bring to a boil. Salt well, and stir in pasta. Cook until pasta is al dente, following manufacturer's instructions. Drain pasta, and serve with short-rib ragu.