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.
In a bowl, mix the ground egusi seeds with a small amount of water to form a thick paste.
Stir the egusi paste into the pot of broth. Mix well to dissolve the paste into the soup.
Add the palm oil, ground crayfish, ground pepper, and seasoning cubes (if using). Stir well.
Simmer the soup for about 10-15 minutes to allow the egusi to cook and thicken the soup.
Add the chopped spinach or bitter leaf (if using) and ground locust beans (if using). Stir well and cook for another 5-10 minutes.
Add the cooked meat back into the soup and stir.
Enjoy your meal!