Grab your spiralizer, use the small noodle blade to quickly spiralize the onion and then the zucchini. Set both aside.
Heat a large soup pot over medium high heat. Once hot, add olive oil and then onions, tomatoes, salt, pepper and red pepper flakes. Cook for 4 to 5 minutes, stirring occasionally, until onions begin to soften and tomatoes begin to blister. Grab a spatula and use it to flatten the tomatoes so they release their juices. Add crushed garlic and cook for 30 to 45 seconds until garlic is fragrant.
Add broth and bring to a boil. Once boiling, remove from heat, add half the pesto, stir to combine and taste for seasoning. You may need to adjust the salt or pepper.
Submerge zucchini noodles in hot broth mixture (they immediately start to cook) and divide out into 4 bowls. Top each with a dollop of remaining pesto and some toasted pine nuts, if desired. Serve and enjoy!
This nutritional information refers to each serving of the entire recipe and not just the products used as ingredients.