Season all sides of the short ribs generously with salt and pepper.
Heat the oil in a large heavy-bottomed pot or Dutch oven set over medium-high heat. When hot, add the short ribs and sear until deeply golden brown on all sides, about 2 minutes per side, working in batches if necessary. Transfer the short ribs to a slow cooker.
In the same pot, add the pancetta and cook, stirring occasionally, for about 3 minutes until crispy.
Add the carrots, celery, onions, garlic, red pepper flakes, salt, and pepper. Cook, stirring, until the veggies are tender and the pancetta is cooked through, 5 to 7 minutes.
Reduce the heat to low. Add the anchovy paste and cook, stirring, for 1 minute.
Add the flour and stir to coat the veggies.
Add the red wine and beef broth. Stir and scrape up all of the browned bits from the bottom of the pot.
Add the canned tomatoes and use the back of your spoon to try and break them up a bit.
Stir in the thyme, oregano, bay leaf, parsley, and basil. Season to taste with more salt and pepper, if needed.
Pour the prepared sauce over the short ribs in the slow cooker. Cover and cook on low for 6 to 8 hours, or until the short ribs are fork-tender.
When ribs are fork tender, discard the bay leaf and transfer the short ribs to a cutting board. Using two forks, shred the meat and discard the bones or unwanted fat/tendons. Place the shredded meat back into the slow cooker and stir. Reduce the heat to warm.
Bring a large pot of water to boil. Cook the pasta until al dente, according to package instructions. Drain.
Divide the pasta among four bowls and top with the short rib ragu. Depending on how meaty your short ribs are, your sauce may be too loose. If this is the case, use a slotted spoon to serve your sauce for best results! Enjoy!