Directions: 1. Melt butter in soup pot over low heat. 2. Add onion and cook until soft but not browned. 3. Add salt, potatoes, and water. 4. Cover and cook over low heat stirring occasionally until potatoes are tender, about 30 minutes. 5. Stir in hot milk and browned hamburger. 6. Combine egg yolk and cold milk, gradually add to hot soup stirring constantly. 7. Add cayenne pepper, and pepper. 8. Garnish with parsley before serving.