1. Cut Brisket 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.
2. 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.
3. Remove brisket; keep warm. Skim fat from cooking liquid. Carve brisket against the grain into very thin slices. Divide brisket evenly among rolls. Close sandwiches.
4. Serve sandwiches with cooking liquid on the side for dipping.
Test Kitchen Tips Beef brisket can be cooked, covered, in an oven preheated to 325°F for 2-1/2 to 3 hours or until brisket is fork tender.
After carving, beef can be returned to cooking liquid and kept warm over low heat until ready to serve, if desired.
You may top your sandwich with sautéed onions or sliced provolone or Swiss cheese.