Season the beef and chicken with a little salt. Simmer them with 1 cup of stock until nearly tender, about 30 minutes. Reserve the cooking liquid.
Blend the onion, garlic, ginger, tomatoes, and Scotch bonnet into a coarse sauce.
Build the soup:
Heat the palm oil in a heavy pot. Add the blended sauce and cook for 10 minutes, stirring occasionally.
Stir in the egusi and cook for 3 minutes. Add the meat, reserved liquid, remaining stock, crayfish, paprika, and salt. Simmer uncovered for 15 minutes.
Fold in the greens and cook for 5 minutes, until tender but still green.
Make the yam and serve:
Bring the water to a simmer in a saucepan. Add the pounded yam flour gradually, stirring constantly, until smooth and stretchy. Cover and steam for 2 minutes.
Shape the yam into portions and serve with ladles of hot egusi soup.
Notes
Stir the egusi after adding stock to prevent scorching.
Use spinach if bitterleaf is unavailable.
Adjust the peppers to suit your preferred heat level.