Preheat your oven to 300°F.
Heat a large pot over medium-high heat.
Add the brisket, browning it for about 6 to 7 minutes on each side.
Add sliced onion and bell pepper to the pot.
Cook for 1 to 2 minutes until they are browned.
Stir occasionally for even cooking.
Pour in the beef stock and BBQ sauce.
Allow the mixture to come to a simmer.
Ensure all ingredients are well combined in the pot.
Cover the pot and transfer it to the preheated oven.
Roast for 2 hours, occasionally basting the brisket with the juices.
After roasting, remove the pot from the oven.
Let the brisket rest for 10 minutes before slicing.
Serve with extra sauce on the side for added flavor.