Season the beef with salt, pepper, garlic powder and ground cumin on both sides.
Preheat 3 tablespoons of oil in a large stock pot.
Sear the beef on all sides, remove from the pot onto a plate, set aside.
To that same pot, add 1 tablespoon oil.
Add the onions, garlic, serrano, and tomatoes.
Season with salt and pepper.
Cook for 5 minutes.
Remove and place in a blender along with 2 cups of water.
Blend until smooth. Set aside until ready to use.
Add the bay leaves and 4 cups of water to the pot.
Return the beef back to the pot.
Bring to a boil and reduce to a simmer.
Cover and cook for 1 ½ hours or until the meat is tender.
Once the meat is ready, remove from the pot and let cool slightly.
Then shred and set aside.
Add the sliced onion and poblano peppers to the pot and cook for 1 minute.
Return the shredded beef to the pot.
Pour in the sauce from the blender into the pot.
Add Worcestershire sauce. Mix well.
Cover and cook for 15 minutes.
Serve and enjoy.