In a large non-reactive pot or enameled Dutch oven, melt the butter over medium heat. Add the finely chopped onions and sauté for 10-12 minutes, stirring occasionally, until softened and lightly golden.

Add the minced garlic and sauté for 1 minute more, until fragrant.

Pour in the crushed tomatoes with their juice, chicken stock, chopped fresh basil, sugar, and black pepper. Stir to combine and bring the mixture to a boil. Once boiling, reduce the heat to low, partially cover the pot with a lid, and simmer for 10 minutes.

For a chunky soup, you can leave it as is. For a smooth, creamy texture, use an immersion blender to purée the soup directly in the pot until the desired consistency is reached.

Alternatively, transfer the soup in batches to a blender and blend until smooth, being careful not to overfill the blender with hot liquid. Pulse a few times initially before blending continuously. Return the puréed soup to the pot and heat over medium.

Stir in the heavy whipping cream and grated Parmesan cheese. Return the soup to a gentle simmer. Taste and adjust seasoning with salt, pepper, or additional sugar if needed to balance acidity. Remove from heat.

Ladle the hot soup into bowls and garnish with extra Parmesan cheese and chopped fresh basil.