1. Peel, cut and wash the sweet potatoes. 2. Add to boiling water and add salt. 3. Add groundnut oil in a dry clean pot. 4. Add chopped onions. 5. Add the chopped vegetables and steamed prawns. 6. Add crayfish, salt, cubes and allow to simmer. 7. Drain the water from the already soft sweet potatoes. 8. Pour the vegetable sauce and mix properly. 9. Serve as desired.