1. Peel and thinly slice the onions and garlic. 2. Peel the potato. 3. Heat a large heavy bottomed pot. 4. Pour into it a little oil. 5. Fry the whole spices for a few seconds. 6. Add butter and reduce heat. 7. Add in the onion and garlic. 8. Fry until soft and lightly coloured. 9. Cut the potato into cubes and add it too to the pot. 10. Cook for 10 minutes. 11. Stir it. 12. Pour in the water. 13. Let it boil. 14. Simmer for 20 minutes. 15. Tip in the spinach. 16. Stir until the leaves have wilted. 17. Mash the contents of the pan. 18. Sieve. 19. Stir in yoghurt. 20. Gently re-heat. 21. Season to taste. 22. Serve either immediately or chill and serve!