In a Dutch oven, heat olive oil over medium-high heat. Brown the beef chunks on all sides.

Add chopped onion and minced garlic, cooking until softened.

In a blender, combine beef broth, guajillo chiles, ancho chiles, cumin, oregano, black pepper, salt, and bay leaves. Blend until smooth.

Pour the blended sauce over the beef in the Dutch oven. Bring to a simmer, then cover and reduce heat to low. Cook for 2-3 hours until the beef is tender.

Once the beef is tender, shred it with two forks and return it to the pot.

Heat corn tortillas in a skillet until warm.

Fill each tortilla with shredded beef, then top with cilantro and diced onion.

Serve with lime wedges on the side for squeezing over the tacos.