In a large stock pot over medium low heat, melt butter. Add garlic, red onion, salt, and pepper. Cook until the onion is translucent, about 5 to 7 minutes. The pieces of onion should break apart very easily with the end of a wooden spoon.
Whisk in the flour and continue cooking until the flour is fragrant and a light brown color.
Whisk in the V8 a little at a time, about a few tablespoons at a time, only adding more V8 once the previous amount is fully whisked in.
Stir in the crushed red pepper flakes and basil.
Add the tomatoes and bring to a boil. Then reduce to a simmer and continue cooking, covered, for 15 minutes. At a simmer the bubbles should be the size of small grapes.
Either using an immersion blender or working in batches with a stand blender, puree the soup.
Remove from the heat and gently stir in the heavy cream.
Serve with crusty bread.