Heat butter in a saucepan and add potatoes, spinach and onion. Saute a few minutes then add stock and bay leaf, bring to a boil, reduce heat and simmer 30 minutes.
Remove about a cup of the vegetables and the bay leaf and puree the soup. Stir in the cream cheese and season to taste. Bring to a simmer and return the vegetables to the saucepan.
Fry the bacon until crispy and stir into the soup. Serve, garnished with parsley.