01 -
In a large skillet over medium heat, cook the ground beef and sliced onions, breaking up the meat, until no pink remains.
02 -
Remove any excess grease from the cooked beef and onion mixture to ensure a balanced texture.
03 -
Place the drained beef and onion mixture evenly in the slow cooker.
04 -
Add quick oats, beef broth, onion soup mix, Worcestershire sauce, garlic powder, and black pepper, stirring thoroughly.
05 -
Cover and cook on low heat for 3 to 4 hours until the flavors meld and the mixture thickens.
06 -
Fifteen to twenty minutes before serving, lay provolone cheese slices over the beef mixture and cover to allow the cheese to melt completely.
07 -
While cheese is melting, lightly toast the brioche buns if desired to help maintain their structure.
08 -
Generously spoon the cheesy beef mixture onto the bottom halves of buns, top, and serve with small bowls of cooking liquid for dipping.