Place garlic in a large pot over medium heat, and cook, stirring, until fragrant.
Add tomatoes, basil, sugar and thyme and cook, stirring occasionally, for 10 minutes.
Add broth, then measure out 1 cup reserved tomato liquid and add to broth. Stir and lower heat to medium-low. Cook, uncovered, for 35–40 minutes, stirring occasionally.
Season with garlic salt and pepper to taste.
In small batches, puree soup in a blender until it is the consistency you prefer.
Return soup to the pot over low heat, stir in heavy cream and mix well.
Adjust seasoning with more garlic salt and pepper if needed, and garnish with croutons, basil and Parmesan cheese.