2. Trim beef of all visible fat and season with salt and pepper. In a large, heavy-bottomed roasting pan, over medium-high heat, quickly brown the meat on all sides in the olive oil. Remove meat, turn the heat to medium and add the onions, leeks, celery, carrots and garlic and cook until vegetables just begin to color and onions are translucent.
2. Return the meat to the pan and add pepper flakes, red wine, beef stock, tomatoes and herbs. Bring to a simmer, cover either with a lid or foil and place in the oven for 2 1/2 hours, or until the meat is very tender and almost falling apart.
3. Strain the liquid from the meat and vegetables. Allow the liquid to sit for a few minutes so that the fat will rise to the surface. Strain off and discard fat. Return the liquid to the pan and over high heat, reduce by approximately 1/3 to concentrate flavors (if desired, thicken with 2 teaspoons of cornstarch dissolved in wine or water). Correct seasoning with salt and pepper if needed.
4. Return the meat and braised vegetables to the pan and warm through. Slice the meat and arrange in shallow bowls along with some of the vegetables. Generously ladle a bit of reduced sauce on top and garnish with roasted potatoes and mushrooms.