Begin by bringing a large pot of salted water to a rolling boil over high heat. Once boiling, add the penne pasta and cook it according to package directions until al dente, usually around 10-12 minutes. When done, reserve ½ cup of the pasta water for later use, then drain the pasta in a colander and set it aside while you prepare the vegetables.

In a large skillet, heat 2-3 tablespoons of olive oil over medium-high heat. Allow the oil to shimmer for about a minute, indicating that it’s hot enough to sauté vegetables.

Add the chopped red onion and carrot to the hot skillet and sauté for about 2 minutes until the onion becomes translucent and the carrot starts to soften.

Incorporate the broccoli florets and sliced bell pepper into the skillet and continue sautéing for an additional 2 minutes, stirring occasionally.

Add the chopped zucchini and yellow squash to the skillet and sauté these for about 2-3 minutes until they are just about softened.

Stir in the minced garlic and diced tomatoes, along with the Italian seasoning. Cook for 2 more minutes, allowing the garlic to become fragrant.

Once the vegetables are perfectly cooked, transfer the sautéed mixture into the pot with the drained pasta. Toss everything together gently.

Drizzle freshly squeezed lemon juice over the pasta and vegetable mixture, then season with salt to taste. Toss everything, adding a bit of reserved pasta water as necessary.

Finally, gently fold in the grated Parmesan cheese and chopped fresh parsley until well combined. Serve immediately.