In a small bowl, combine all dry rub seasonings. Reserve 1 1/2 tablespoons of the mixture for the BBQ sauce. Rub both sides of brisket with dry rub.
Place brisket in a large resealable plastic bag. Refrigerate overnight.
In a large skillet over medium-high, heat oil. Sear brisket 2 to 3 minutes on each side.
Arrange onion wedges in bottom of a slow cooker crock. Place brisket on top of onion.
Cover slow cooker and cook on HIGH for 4 to 4 1/2 hours or LOW for 6 1/2 to 7 hours. Brisket should be tender, but not falling apart.
Remove brisket to cutting board. Let stand 10 minutes, then cut in 1/4-inch thick slices.
For BBQ Sauce: In a medium saucepan over medium-high, melt butter. Add onion and garlic. Cook until onion is tender, about 2 minutes. Add remaining ingredients and reserved 1 1/2 tablespoons dry rub mixture and whisk until well blended. Reduce heat to low and simmer for 30 minutes. Serve with brisket.
In a small bowl, combine all dry rub seasonings. Reserve 1 1/2 tablespoons of the mixture for the BBQ sauce. Rub both sides of brisket with dry rub.
Place brisket in a large resealable plastic bag. Refrigerate overnight.
In a large skillet over medium-high, heat oil. Sear brisket 2 to 3 minutes on each side.
Arrange onion wedges in bottom of a slow cooker crock. Place brisket on top of onion.
Cover slow cooker and cook on HIGH for 4 to 4 1/2 hours or LOW for 6 1/2 to 7 hours. Brisket should be tender, but not falling apart.
Remove brisket to cutting board. Let stand 10 minutes, then cut in 1/4-inch thick slices.
For BBQ Sauce: In a medium saucepan over medium-high, melt butter. Add onion and garlic. Cook until onion is tender, about 2 minutes. Add remaining ingredients and reserved 1 1/2 tablespoons dry rub mixture and whisk until well blended. Reduce heat to low and simmer for 30 minutes. Serve with brisket.