Slice the onion thinly and cut the bell peppers into 1/4 inch strips. Mince the garlic.
Season both sides of each flank steak with adobo seasoning. Cut each in half to fit in pot.
Heat the oil in large heavy-bottomed Dutch oven over medium high heat. Add the steaks to the pot and sear each side, working in batches, until browned, about 10 minutes.
Place the seared meat to a plate and lower heat to medium on Dutch oven. Add the onions, half the bell peppers and garlic. Cook, stirring occasionally, about 10 minutes.
Add the sofrito, tomato sauce, Sazon, pepper and beef broth. Stir and bring mixture to a boil. Return the beef to pot and push under the vegetables. Lower heat and simmer, covered for 45 minutes.
Stir in remaining bell peppers, olives, pimentos, and capers. Cover pot and continue to simmer for 90 minutes. Meet should almost fall apart when you pick it up.
Carefully transfer meat to bowl and shred meat with fingers or two forks. Bring the vegetables and sauce to a boil and add the meat, cook for another 10 minutes uncovered. Serve over white rice with cilantro sprigs for garnish (See Note 4).
Video
Notes
Cut each flank steak vertically in half, not lengthwise!
I like to use different colored bell peppers like red, green, yellow. We eat with our eyes!
Sofrito is a thick, salsa-like Latin cooking base made of tomato, onion, green peppers, culantro and garlic, saves you prep time in the kitchen. Sofrito comes in a 8 oz tall jar, I use about half of it. Feel free to use the entire 8 oz if you prefer a more punch of flavor and or substitute with a 4 oz of tomato paste instead if you like and add a quarter cup of water.
As another option to serve: Ropa Vieja can also be served with black beans and fried plantains with limes.