This works great with cheaper cuts of meat like chuck, shank, or brisket. Stay away from something like rib eye. Don't limit yourself to just using this for for tamales. It can be used in kreplach, egg rolls, or just put on a hamburger bun and eaten as a sandwich.
Add the olive oil to medium sauce pot and place over medium heat. Add the onions and saute until the onions start to brown.
Add the garlic and bell pepper to the pot and continue sauteing until the peppers start to soften and the garlic starts to brown.
Add the beef, BBQ sauce, and water. Turn down to low, cover, and simmer for about 10 minutes, stirring regularly to prevent burning. Allow to cool before using as filling