Trim the ends of the zucchini and spiralize them into noodle shapes using a spiralizer. Set aside.

In a large skillet, heat olive oil over medium heat. Add minced garlic and red pepper flakes. Sauté for 30 seconds.

Add the zucchini noodles to the skillet and cook for 5 to 7 minutes until tender but al dente. Remove from heat.

Stir in the diced tomatoes, basil leaves, and Parmesan cheese with the zucchini noodles. Cook for 1 minute.

In the same skillet, mix cornstarch with cold water to create a slurry. Bring the leftover sauce to a simmer, then whisk in the slurry for 1 minute until thickened.

Return the zucchini noodles to the skillet and toss in the thickened sauce. Serve garnished with additional Parmesan cheese and basil.