Trim the beef of excess fat, then season it with salt and Sazon to taste.
Heat 2 tablespoons of oil in a Dutch oven or deep skillet over medium heat, and sear the beef on both sides until browned (3-4 minutes per side). Set it aside.
Add more oil if necessary, then toss in the bay leaves, onions, garlic, bell peppers, tomatoes, tomato sauce, thyme, paprika, cumin, and more Sazon. Saute for 3-5 minutes, then pour in the broth. Turn off the heat and pour about ¾ of the sauce into the slow cooker (reserving the rest of the sauce for later).
Add the meat back, cover with the lid or aluminum foil, and simmer on low until tender and easily shredded (3-4 hours). You could also braise it in a 325℉ (160℃) oven. Check the liquid level occasionally and add more broth if needed. Remove the steak from the pan, and set it aside to cool slightly. As soon as you can touch it without burning yourself, shred it using two forks.
Add the shredded beef back to the pan with the sauce, and stir well. Adjust seasoning with salt and pepper to taste, and garnish with chopped parsley or cilantro. Serve with rice, black beans, and tostones.