In the bottom of a sprayed or lined slow cooker, place onion and carrots. Season roast liberally with salt and pepper and place on top of onion and carrots.

In a bowl, stir together broth, vinegar, garlic, sugar and Worcestershire sauce. Pour over beef.

Cook on low 6-8 hours or high 4-6 hours.

Remove roast. Slice or shred beef and place on a serving platter. Using a slotted spoon, remove onions and carrots and place around beef on platter.

Either serve the cooking liquid in a bowl on the side or if you prefer a thicker “sauce”, pour liquid in a pan and stir in a mixture of 1 T cornstarch mixed with water. Bring to a boil and cook until thickened; about 5 minutes.