Bring a large pot of salted water to a rolling boil. Add the penne pasta and cook according to package instructions until al dente, usually about 10–12 minutes. Reserve ½ cup of pasta water before draining.

While the pasta cooks, heat a deep skillet over medium-high heat. Pour in olive oil and allow it to shimmer, which should take about a minute.

Add the chopped red onion and sliced carrot to the skillet. Sauté for about 2 minutes, stirring occasionally, until softened and fragrant.

Add the broccoli florets and diced red bell pepper into the skillet. Sauté for another 2 minutes, allowing the vegetables to maintain a bit of crunch.

Stir in the yellow squash and zucchini, cooking for an additional 2 to 3 minutes until colors pop and a perfect tender yet crisp texture is achieved.

Add minced garlic and halved grape tomatoes to the skillet, stirring well. Sauté for another 2 minutes, letting the garlic become fragrant and the tomatoes soften.

Gently toss in the drained pasta and mix them together well, allowing the pasta to embrace the vegetables.

Drizzle fresh lemon juice over the pasta and veggies, then season with salt to taste. Toss again, adding reserved pasta water as needed to create a silky sauce.

Stir in grated Parmesan cheese while the pasta is still warm, allowing it to melt into the dish. Top with freshly chopped parsley before serving.