In a large pot or Dutch oven, heat the olive oil over medium heat.
Add the diced onion and sauté for 2-3 minutes until it becomes translucent.
Stir in the minced garlic and cook for another minute until fragrant.
Add the diced bell pepper, zucchini slices, cherry tomatoes, and broccoli florets to the pot. Sauté for 5 minutes, stirring occasionally.
Add the penne pasta, vegetable broth, Italian seasoning, salt, and pepper. Stir well to combine.
Bring the mixture to a boil, then reduce the heat to low. Cover the pot and let it simmer for about 10-12 minutes, or until the pasta is al dente and the vegetables are tender. Stir occasionally to prevent sticking.
Once cooked, remove the pot from heat. If the pasta is too thick, add a little more vegetable broth to reach your desired consistency.
Serve the pasta primavera hot. Top with grated Parmesan cheese and fresh basil leaves if desired.