Place dry pasta, onion, garlic, cherry tomatoes, and zucchini into a large, wide-bottomed pot or Dutch oven.
Pour vegetable broth and olive oil over the ingredients, then add oregano, red pepper flakes, salt, and pepper.
Bring the mixture to a boil over high heat.
Once boiling, reduce heat to medium-high and simmer for 9 to 11 minutes, stirring frequently with tongs to prevent sticking.
Continue cooking until the pasta is al dente and the liquid has reduced into a thick sauce that coats the noodles.
Stir in the fresh baby spinach during the last 60 seconds of cooking until wilted.
Remove from heat, stir in the grated Parmesan cheese, and garnish with fresh basil before serving.