Heat the olive oil in a large saucepan over medium heat. Add the onion and cook for 5 minutes until soft.
Add the garlic and cook for 1 minute until fragrant.
Pour in the chopped tomatoes, vegetable stock, sugar, dried basil, salt and pepper. Bring to a simmer.
Cook for 15 minutes, stirring occasionally, until the soup has thickened slightly.
Remove from heat and blend with a stick blender until completely smooth.
Stir in the cream and most of the fresh basil, reserving a few leaves for garnish.
Ladle into bowls and top with the remaining basil leaves.