Dice onion and zucchini into small cubes; set aside.
Pre-heat a pot over medium heat; add canola oil to the pot.
Add diced onions to the pot and saute until transparent.
Add diced zucchini, mix and saute for a couple of minutes.
Add the entire content of the canned diced tomatoes; stir in the tomato paste.
Add the granulated sugar, salt and red pepper flakes; stir well.
Simmer for a few minutes and then add warmed chicken stock.
Lower heat to medium-low; stir, cover and cook for about 30 minutes; stir once in awhile.
Add fresh basil and cook for a couple more minutes.
Remove soup from heat and use an immersion blender to blend until there are no more chunks or, if you prefer, leave a few little chunks.
Place the pot back on the stove, still on medium-low; stir in heavy cream and freshly grated Parmesan cheese.
Taste to see if you need to add more salt.
Cook for just a couple more minutes.
Remove from heat and serve.
