Heat the oil in a large skillet over medium-high heat. Add the brisket and brown on all sides. Transfer the brisket to a slow cooker.
Add the onion and bell pepper to the skillet and cook until softened, about 5 minutes.
Add the buffalo sauce, Worcestershire sauce, apple cider vinegar, brown sugar, garlic, chili powder, oregano, cumin, and smoked paprika to the skillet and stir to combine. Pour the sauce over the brisket.
Cover and cook on low for 6-8 hours or on high for 4-5 hours, or until the brisket is fork-tender.
Remove the brisket from the slow cooker and let rest 10 minutes before slicing.
Serve with extra sauce on the side.
Interesting Facts
The slow cooker is a great way to make a tender and flavorful brisket with minimal effort.
Buffalo sauce is a combination of hot sauce, butter, and spices.
The brisket can be served with mashed potatoes, burgers, and sandwiches.