The information presented here is taken from allrecipes.com
This ropa vieja is great served on tortillas or over rice. Add sour cream, cheese, and fresh cilantro on the side.
Heat vegetable oil in a large skillet over medium-high heat. Add flank steak and cook until browned, about 4 minutes per side.
Transfer steak to a slow cooker; pour in beef broth and tomato sauce. Add tomato paste, bell pepper, onion, garlic, cumin, cilantro, olive oil, and vinegar; stir until well blended.
Cover and cook on Low for up to 10 hours, or on High for 4 hours.
Shred steak in the slow cooker with two forks.