Boil the cassava: Peel and cut cassava into chunks. Boil in salted water until tender, then drain and remove any stringy core. Mash with butter, milk, salt, and pepper. Add cheese if desired.
Prepare the filling: Season beef with green seasoning, garlic powder, salt, black pepper, and chopped chadon beni. Heat oil in a skillet, sauté onion, garlic, and celery. Add seasoned beef and cook until browned.
Add remaining ingredients: Stir in tomato paste, Worcestershire sauce, cooking wine, chopped tomato, bell pepper, scallions, and broth. Simmer until thickened.
Assemble: Layer the beef in a greased baking dish, spread mashed cassava on top, and smooth it out. Add cheese on top if desired.
Bake: Bake at 375°F (190°C) for 25–30 minutes, until golden on top. Then broil for 5 minutes.
Serve: Cool for 5–10 minutes before slicing and serving.
