In a large pot, place the flank steak and cover it with water. Add the sliced onion, minced garlic, cumin, oregano, salt, pepper, lime juice, chicken broth, and bay leaf. Bring to a boil over medium-high heat, then reduce the heat to low and simmer for about 2 hours, or until the meat is tender.

Remove the flank steak from the pot and let it cool slightly. Shred the meat using two forks, discarding any excess fat.

In a large skillet, heat the olive oil over medium-high heat. Add the shredded beef and cook for about 5-7 minutes, stirring occasionally, until it gets crispy and browned.

Serve the vaca frita garnished with fresh cilantro and lime wedges on the side.