Preheat the oven to 325 degrees F.
Pat the beef dry with a paper towel. Season the roast all over with 1 Tbsp kosher salt and 1 1/2 teaspoons pepper. Dredge the whole roast in flour, including the ends. In a large Dutch oven, heat 2 tablespoons olive oil over medium heat. Add the roast and sear for 4 to 5 minutes, until nicely browned. Turn and sear the other side and then turn and sear the ends. This should take 4 to 5 minutes for each side. Remove the roast to a large plate.
Add 2 tablespoons olive oil to the Dutch oven. Add the carrots, onions, celery, leeks, garlic, a little salt and pepper and cook over medium heat for 10 to 15 minutes, stirring occasionally, until tender but not browned. Add the wine and Cognac and bring to a boil. Add the tomatoes, beef stock, bouillon cube, 2 teaspoons salt, and 1 teaspoon pepper. Tie the thyme and rosemary together with kitchen string and add to the pot. Put the roast back into the pot, bring to a boil, and cover. Place in the oven for a total of 3 hours, lowering the oven temperature to 250 degrees after the first hour. You want the sauce to maintain a simmer, but cook low and slow. I also flip the beef to ensure even soaking in the sauce, about half way through.
Remove the roast to a cutting board. Remove the herb bundle and discard. Skim off as much fat as possible from the sauce. Transfer half the sauce and vegetables to a blender or a food processor fitted with the steel blade and puree until smooth. Pour the puree back into the pot, place on the stovetop over low heat, and return the sauce to a simmer. Taste for seasonings. Remove the strings from the roast, and tear the meat into large pieces - I try to shred it like you would with chicken, but in large bites. Return the beef to the sauce, and serve over polenta, mashed potatoes, or just on its own. Garnish with freshly chopped parsley.