300g fresh spinach
250 ml chicken or vegetable stock   
100 ml cream   
salt  
pepper 
50g butter

Clean the spinach in a bowl of water and drain; then place the spinach in a saucepan with a few tablespoons of water and cover with a lid. Simmer over moderate heat, then drain and let it cool. Squeeze it dry and chop finely with a sturdy knife on a chopping board. Return the spinach in the saucepan and add enough stock to almost cover it. Bring the soup to the boil and simmer for a few minutes. Take the saucepan off the stove and puree the soup using a hand blender. Pour the soup back in the pan, add the cream to get the right consistency and reheat the soup. Season with salt and pepper, and add the butter.