Heat a nonreactive pot or enameled dutch oven over medium heat. Add butter then add chopped onions. Sauté for 10 to 12 minutes, stirring occasionally, until softened and golden.
Add minced garlic and sauté for 1 minute until fragrant.
Add crushed tomatoes with their juice, chicken stock, chopped basil, sugar (or add sugar to taste), and black pepper. Stir together and bring to a boil then reduce heat, partially cover with lid and simmer for 10 minutes.
You can leave your soup with a chunky consistency, but if you like a blended/creamy soup, use an immersion blender to blend the soup in the pot to the desired consistency or transfer to a blender in batches and blend until smooth (being careful not to over-fill the blender with hot liquid and pulse a few times initially to get it started), then return blended soup to the pot over medium heat.
Add heavy cream, parmesan cheese and return to a simmer. Season to taste with salt and pepper if needed and turn off the heat.
Ladle into warm bowls and top with more parmesan and chopped fresh basil.
