Tomato soup is a year-round staple, but it's at its best when made with ripe summer tomatoes.
Melt butter in a medium saucepan over medium heat. Add onions and garlic, and cook, stirring, until onions are translucent, about 3 minutes. Add wine, tomatoes, salt, and pepper. Cook just until tomatoes are falling apart, about 5 minutes. Stir in basil, and remove from heat.
Let cool slightly. Transfer tomato mixture to a blender, filling the jar no more than halfway; work in batches if necessary. Cover lid with a clean dish towel, and press lid securely in place while blending soup.
Return soup to saucepan. Add cream, and adjust consistency with water if necessary. Season with salt and pepper.