Prep the beef. Pat the beef shanks dry with paper towels. Tie a piece of kitchen twine around the circumference of each beef shank to help them keep their shape as they cook. Liberally season both sides of the shanks with salt and pepper, then let them rest for 30 minutes. Use a piece of kitchen twine to tie the rosemary and thyme into a bundle.
Preheat an oven to 325 F.
Sear the beef shanks. Heat the oil in a wine braiser over medium heat. Once the oil is hot, sear the beef shanks for 3-5 minutes per side, until deeply browned. Transfer to a plate and set aside.
Saute the veggies. Add the diced onion, carrots, and celery to the pan and cook, stirring occasionally, until the vegetables are starting to brown. Stir in the garlic and cook for 1 minute more. Stir in the dijon, tomato paste, and beef bouillon paste and stir well so the veggies are coated.
Build the braise. Sprinkle the flour over the top and stir to combine. Cook for 2-3 minutes, stirring often, then add the wine and beef stock. Stir well, season with salt and pepper, and then nestle the beef shanks in with the herb bundle and bay leaves.
Braise the beef shanks. Cover the braiser with a lid and transfer to the oven for 2 1/2 hours. Remove the lid, flip the beef shanks over, and return to the oven uncovered for another 30 minutes to an hour (basting every 10 minutes with pan sauces), until the beef is very tender and easily shredded with a fork. Remove from the oven, cover, and let the beef rest in the juices for 20 minutes. Season the sauce to taste with salt and pepper and serve right away.