Combine tomatoes, juice/and or stock in saucepan. Simmer 30 minutes. Puree, along with the basil leaves, in small batches, in blender, food processor (or better yet, one of those handy hand-held food blenders, right in the cooking pan).
Return to saucepan and add cream and butter, while stirring over low heat. Garnish with basil leaves and serve with your favorite bread.