Bring a large pot of salted water to a boil, and cook the penne pasta when boiling following the directions on the box.
In a large skillet, saute' the chopped onion in a few tablespoons of olive oil, over medium heat.
Add the zucchini cut in small pieces. Saute' over medium-high flame for 7-10 minutes. Season with salt.
Add the pancetta cut in strips and saute' for a couple of more minutes.
In a bowl prepare the ricotta by mixing it with a pinch of salt, a sprinkle of pepper, the Parmesan cheese and about a 1/4 cup of hot water from the pot where the pasta is cooking. Mix and make it creamy.
Drain the pasta and toss it in the skillet with the zucchini and the ricotta. Serve immediately.