Blanch the tomatoes until skin comes loose, then skin, seed, and chop coarsley. Saute onion in butter a few minutes, then add all ingredients except the milk and cream. Simmer for about 25 minutes, and remove the cloves. Transfer to a blender or food processor, and puree. Add half and half, and the milk. (If preparing before-hand, put aside in the refrigerator at this point.) Heat up in a sauce pan and sprinkle chives on top before serving.