1. 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.

2. 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.

3. Return soup to saucepan. Add cream, and adjust consistency with water if necessary. Season with salt and pepper.