I have had this recipe since 1993. It came from a Safeway sales flier and they got it from Cooking Light Magazine. Crockpot cooking is a favorite way to cook in our home and this is one of our favorite recipes.
Trim fat from roast. Place roast and next six ingredients in a slow cooker. Cover and cook over low heat for 11 hours or until roast is tender. Remove roast from slow cooker; let stand 10 minutes. Separate roast into bite-size pieces, and shred meat with two forks; set aside.
Strain cooking liquid, discarding solids. Skim fat from surface of cooking liquid and discard. Place cooking liquid in a saucepan and bring to boil. Remove from heat.
Line bottom halves of each bun with a lettuce leaf. Top each with shredded beef and top half of bun. Serve hot cooking liquid as a dipping sauce.
Our family likes to have mayonnaise, barbeque sauce and A1 sauce on the table so we can each top our meat according to our personal taste. I do reserve some of the onion, as my husband likes to add the cooked onion to his sandwich. Do not expect leftovers, this meat is so flavorful and tender .... my, oh my!!!