Slow-cooked beef Brisket has never tasted so good. Sliced thin and stacked on a hoagie roll, you almost don't need the au jus. Almost.
Cut beef Brisket Flat Half into 3 to 4 pieces. Heat oil in stockpot over medium heat until hot. Place beef brisket in stockpot; brown pieces evenly. Remove brisket from stockpot; set aside.
Add onions to stockpot; cook on low heat 18 to 22 minutes until lightly caramelized, stirring occasionally. Add broth, soy sauce, soup mix and garlic. Return brisket to stockpot; bring to a boil. Reduce heat; cover tightly and simmer 2-1/2 to 3 hours or until brisket is fork-tender.
Remove brisket; keep warm. Skim fat from cooking liquid. Carve brisket against the grain into very thin slices. Divide brisket evenly among rolls and top with prepared onions. Top with cheese, as desired. Close sandwiches.
Serve sandwiches with cooking liquid on the side for dipping.
Test Kitchen Tips Avoid lifting the lid of your cooking vessel, which releases valuable heat and moisture and can significantly increase the cooking time.