Begin by bringing a large pot of salted water to a rolling boil. Add the penne pasta and cook until al dente, about 8-10 minutes. Reserve ½ cup of pasta water before draining.

In a large skillet, heat olive oil over medium-high heat. Once shimmering, add chopped red onion and sliced carrot. Sauté for about 2 minutes until translucent.

Add broccoli florets and bell pepper strips. Stir frequently and cook for an additional 2 minutes until they are bright in color.

Stir in the sliced zucchini and squash, cooking until they start to soften, about 2-3 minutes.

Add minced garlic, halved cherry tomatoes, and Italian seasoning. Sauté for another 2 minutes until fragrant.

Transfer sautéed vegetables into the pot with the drained pasta. Mix the reserved pasta water and lemon juice until combined.

Stir in grated Parmesan cheese and finely chopped parsley. Season with salt and pepper. Serve immediately.