To make the beef, heat a large sauté pan over high heat. Rub the chuck roast with lots of olive oil and season liberally with salt and pepper. Place the beef into the pan and sear on all sides until just brown. Remove the beef and set aside.
Place the rosemary and garlic into the bottom of the slow cooker to make a bed for the beef. Place the beef over top and pour in the tomato purée, red wine and beef stock.
Cook on high for 4 hours or low for 6 hours. (The dish can be cooked overnight or you can make it a day ahead of time. Just reheat the beef in the in the pot on the stove over a low heat until hot.)
After the beef is cooked, remove the beef to a serving platter and slice. Strain two cups of the leftover cooking liquid into a small saucepot and cook over high heat to reduce by half. Pour over the beef just before serving.
To make the salsa verde, place the parsley, oregano, capers, red wine vinegar and Dijon into a food processor and pulse until finely chopped. Add in the shallot, olive oil and season with salt and pepper. Run the food processor just until the oil is combined, just a few seconds. Serve alongside the beef.