In a large pot or Dutch oven, heat the olive oil over medium heat.
Add the diced onion and sauté until softened, about 3-4 minutes.
Stir in the minced garlic and cook for an additional minute until fragrant.
Add the zucchini, bell pepper, cherry tomatoes, and broccoli to the pot. Sauté for about 5 minutes until the vegetables begin to soften.
Stir in the pasta, vegetable broth, Italian seasoning, salt, and pepper. Bring the mixture to a boil.
Once boiling, reduce the heat to medium-low, cover the pot, and let it simmer for about 10-12 minutes, stirring occasionally until the pasta is cooked and the liquid is mostly absorbed.
Remove the pot from heat and, if desired, stir in grated Parmesan cheese for added flavor.
Serve hot, garnished with fresh basil leaves if using.