Start by patting your beef brisket dry with paper towels. Mix together salt, black pepper, smoked paprika, garlic powder, onion powder, and optional chili powder. Rub this spice mixture all over the brisket.

Heat olive oil in a large skillet over medium-high heat. Once shimmering, sear the brisket for 2-3 minutes on each side until golden brown.

Transfer the seared brisket to a slow cooker. Pour in beef broth, barbecue sauce, Worcestershire sauce, Dijon mustard, brown sugar, sliced onions, and minced garlic.

Set slow cooker to LOW and cook brisket for 8 hours, or HIGH for 4 hours until fork-tender.

Remove brisket from slow cooker after cooking and let it rest for 10 minutes.

Shred the brisket using two forks, reserving about ½ cup of cooking liquid.

Melt butter in a skillet, add the reserved cooking liquid, brown sugar, and Worcestershire sauce. Stir, then mix in the shredded brisket. Cook for 5-7 minutes until caramelized.