Cook the noodles in five cups boiling water for about ten minutes. Drain and refresh in cold water.
Drain and set aside. Melt the butter in a pan, add onions and sauté till soft and translucent.
Add spinach and continue to cook for two to three minutes.
Add yogurt, cheese, lemon juice, salt, black pepper powder and nutmeg. Mix well and cook on low heat without boiling.
Add the noodles and toss well. Serve immediately.