In a heavy bottomed pot (like a Dutch oven), heat olive oil over medium-high heat. Add garlic and saute for 30 seconds, until fragrant. Add onion and cook, stirring as needed, until translucent, about 8 minutes.
Add San Marzano peeled tomatoes (juice and all), chicken stock, and sugar. Bring to a low simmer. Cook uncovered, for 12 minutes or until it has thickened.
Add the heavy cream, basil, oregano, red pepper flakes and season to taste with salt and pepper.
Using an immersion blender (or carefully transfer soup to a blender), puree soup until there are no large chunks left. If using a regular blender, be careful and watch for hot splatters. Throw a kitchen towel over the blender top to be safe or let it cool slightly.
Stir in parmesan cheese and serve topped with croutons, if desired!
