In a small bowl, combine salt, pepper, onion and garlic powders and sprinkle over the roast. In the slow cooker, combine broth, vinegar and sugar, and mix well. Add the beef and vegetables, cover and turn the slow cooker to LOW. Cook for approx. 8-10hrs.
Half an hour before serving, remove the beef and vegetables to a plate and tent with foil. Skim fat from the broth. Turn heat to HIGH. Mix flour and water together in a small bowl to make a slurry, and slowly add to the broth, pouring through a strainer to avoid lumps. Replace lid and cook for 30 min.
Slice beef, serve with gravy, vegetables and your favourite side.
The slow cooker is the real hero in this braised pot roast. Get a head start by prepping the beef, veggies and broth the night before.