Heat olive oil in a heavy pot over medium heat. Add diced onion and cook for 6 to 8 minutes, stirring, until softened.
Stir in minced garlic and cook for 30 seconds. Add crushed tomatoes, broth, dried basil, optional sugar, salt, and pepper.
Bring to a gentle simmer, partially cover, and cook for 20 minutes, stirring occasionally.
Blend the soup until smooth, working in batches if necessary. Return it to the pot.
Reduce heat to low and stir in cream. Warm gently without boiling, taste, adjust seasoning, and serve.
Ladle the hot soup into bowls and serve with crusty bread, if desired.
