Pour olive oil into a pot, add peeled and halved garlic cloves. Sauté for a moment, then add peeled and diced shallots or regular onion. Add chili pepper sliced and seeded and sauté on low heat for about 5 minutes, stirring occasionally.
Pour in white wine and simmer for half a minute. Add tomato purée and broth, bring to a boil. Meanwhile season with pepper and add salt if needed. Simmer uncovered for about 10 minutes.
Add dried oregano, Worcestershire sauce and leaves from half of the basil bunch. Blend with an immersion blender "giraffe" but not necessarily into a smooth cream. Simmer for about 5 more minutes uncovered, stirring occasionally.
Remove from heat, add butter and let it melt. Pour in sour cream and mix. Serve with cheese croutons and remaining basil.