Wash spinach and cut into small pieces. Fry onions and garlic in oil until slightly golden. Add spinach and fry together over medium heat until cooked. Let it cool down completely in the refrigerator.
Add salt and pepper to yogurt to taste and beat well until the yogurt is a free-flowing liquid. Add spinach to yogurt and mix well. The mix should be thick and homogeneous. This delicious side-dish is now ready to serve.