1. In a large pot, over medium heat, cook onion and garlic in olive oil.

2. Add tomatoes and broth, bring to a simmer, reduce heat to low, add basil, and cook for 30 minutes.

3. Add heavy cream and use an immersion blender to blend until smooth.

4. Place sour cream in a freezer bag and snip off the corner.

5. Pour soup into bowls.

6. Draw rings of sour cream on top of the soup, then use a skewer or toothpick to pull lines through the sour cream, creating a spider web effect.