In a large pot, combine the beef (or goat meat) with the cow's foot or shank (if using), chopped onion, minced garlic, and minced ginger.
Add enough water to cover the meat and bring to a boil. Reduce the heat and simmer for about 1-2 hours, or until the meat is tender. Skim off any foam that forms on the surface.
Remove the meat and cow's foot (if using) from the pot and set aside. Strain the broth to remove any solids, then return the broth to the pot.
Add the ground achi, ground crayfish, ground pepper, and seasoning cubes (if using) to the broth. Stir well.
Simmer the soup for about 10 minutes to allow the flavors to meld.
Add the palm oil to the soup and stir. Continue to simmer for an additional 5 minutes.
In a separate pot, boil the yam or plantain chunks in salted water until tender. Drain and set aside.
If using spinach or bitter leaf, blanch it in boiling water for a few minutes, then drain and chop.
Add the cooked meat back into the soup and stir.
Enjoy your meal!