Take a large pot with a heavy base and turn on your stove to medium. Add one tablespoon of olive oil in the pot and add the chopped onions, sauté the onions until they are tender and translucent. This will take around 5 minutes. Chop the tomatoes roughly and add them into the same pot. Pour in 2 ¼ cup of your favourite barbeque sauce and turn the heat to medium high. Let the sauce simmer for 10 minutes on increased heat. Add the chunk of beef and lower the heat. Cover the pot and let it simmer for around 3 hours. The meat should be very soft and tender. Don’t forget to stir from time to time.
After the meat is cooked thoroughly and is soft, remove it from the pot onto a plate. With the help of a fork and a knife, cut small pieces of it and put them to one side for the time being. Let the pot stay on the stove and increase the heat to medium high. Take the lid of the pot and let it simmer. Keep an eye on the liquid when it thickens. Keep stirring in between so that the liquid doesn’t stick to the bottom and burn.
Return the pieces of the beef back to the pot with the liquid. Let them get warm on medium heat. Season the mixture with salt and pepper to taste. Spread it on toasted bread or warm hamburger buns and serve.