Make a vegetable broth and pass through a sieve to remove solids. Return broth to pot and add butter and quartered tomatoes. Bring to a minimum simmer (a small bubble here and there) and leave until tomatoes are very soft (about 1.5 hrs). Pass through an Italian food mill to remove seeds and peels. Let cool and put through the blender in batches to make it velvety. If served the traditional way, add whipping cream to taste and reduce over medium heat until thickened. Serve with rice and a dollop of sour cream. This soup may also be served without dairy or garnished with some Fage yogurt (I use 2%) and rice. Without dairy, it freezes very well.