Slice the zucchini lengthwise, then cut it into ½-inch thick half-moons. Quarter the button mushrooms and set aside.

Bring salted water to a boil in a large pot and cook the penne pasta according to package instructions until al dente, about 8-10 minutes.

Heat olive oil in a large skillet over medium heat. Sauté the chopped onion for about 5 minutes until soft, then add minced garlic and cook for 1-2 minutes.

Add the sliced zucchini to the skillet and sauté for 3-4 minutes until slightly tender and vibrant in color.

Stir in the quartered mushrooms, and sauté them for another 5 minutes until tender and well combined with the zucchini and aromatics.

Once the pasta is al dente, reserve about a cup of pasta water and drain the remaining water.

In the skillet, add the drained penne pasta and toss everything together, adding reserved pasta water as needed for a cohesive texture.

Sprinkle in salt, red chilli flakes, and dried parsley, stirring to integrate the flavors. Fold in cheese until melted and serve immediately.