Directions

1. 1

   Place the beef roast in a large pot or Dutch oven. Peel and quarter the onion, then add it to the pot with the meat. Add just enough water to partially cover the roast. Bring to a boil, then reduce heat to low, cover, and simmer for 5 to 6 hours until the meat is very tender and shreds easily with a fork.

2. 2

   Remove the cooked roast from the pot and let it cool slightly. Discard the cooking liquid and onion. Shred the beef into bite-sized pieces using two forks, removing any excess fat.

3. 3

   In a small bowl, whisk together the ketchup, cola, Dijon mustard, and Worcestershire sauce until combined.

4. 4

   Return the shredded beef to the pot and pour the barbecue sauce mixture over it. Stir well to coat all the meat with the sauce.

5. 5

   In another small bowl, mix the cornstarch with the water until smooth, stirring out any lumps.

6. 6

   Pour the cornstarch slurry into the beef mixture and stir constantly. Bring the mixture to a simmer over medium heat and cook for 2 to 3 minutes, stirring occasionally, until the sauce thickens and becomes glossy.

7. 7

   Reduce heat to low and let the mixture simmer gently for 10 more minutes, allowing the flavors to blend and the sauce to coat the beef evenly.

8. 8

   Toast the sandwich buns lightly if desired. Spoon the barbecue beef onto each bun and serve hot.