Wash spinach and cook in a large pan with 2/3 tbs. of water for 10 minutes. Drain well and puree in a blender. Keep aside.
Heat butter in a saucepan, add onion and sauté till tender. Stir in Maida and blend it with a wooden spoon. Pour milk and stock gradually. Stir well to avoid formation of lumps.
When smooth, blend in Melam garam masala and powdered chicken cube along with spinach puree. Adjust seasonings according to taste. Whip 2 tbs. of cream and pour over the soup and serve.