Heat olive oil in a large pot over medium heat. Add chopped onions and sauté until translucent, about 5 minutes.

Add minced garlic and cook for another minute until fragrant.

Add chopped tomatoes, vegetable broth, sugar, and dried basil. Stir well and bring to a boil.

Reduce heat to low, cover, and simmer for 20 minutes, stirring occasionally.

Use an immersion blender to puree the soup until smooth. Alternatively, transfer to a blender in batches.

Stir in heavy cream and season with salt and pepper to taste. Simmer for another 2-3 minutes.

Garnish with fresh basil leaves before serving.