Melt butter in large stockpot over medium heat. Add onion and saute' 1 to 2 minutes. Reduce heat to low and add remaining ingredients except stock, cream and parsley. Cook until vegetables are soft but not brown, about 20-25 minutes.
Add stock and bring to boil over medium high heat. Reduce heat and simmer about 10 minutes. Cook slightly.
Transfer to blender of processor in batches and puree to smooth. Taste and adjust seasoning. Return to stockpot, place over medium heat and gradually stir in cream. Heat through but do not boil. Garnish with parsley.
From Le Cellier Restaurant, Santa Montica, California. Recipe shared by Cate Vanicek