Preheat the oven to 275ºF
Season the short ribs aggressively with kosher salt and black pepper, and dredge them in the flour, shaking off the excess.
In a large, heavy-bottomed ovenproof skillet or Dutch oven, heat the olive oil over high heat until light smoke
Place short ribs five at a time, in the hot oil and sear until deep brown on all sides, about 15 minutes per batch. Transfer the short ribs to a plate and set aside.
Place short ribs gently in braising liquid making sure short ribs are completely submerged. Cover and place in center of oven. Cook for 2 hours.
Uncover the skillet and continue to cook for 30 minutes, or until the meat is fork-tender. Remove from the oven and use a ladle or a large kitchen spoon to skim the fat from the braising liquid.
Gently remove carrots, celery root (for plating), remove bay leaves and all herbs
In Vita-Mix blender add remaining braising liquid with remaining vegetables and puree on high for 3 minutes
Strain through Chinois and ladle over short ribs