Meanwhile in a nonstick skillet sauté onion with 1 tablespoon olive oil for 3 minutes over medium heat.
Add butternut squash, sauté for five minutes then add broth, simmer until thoroughly cooked. Season with salt and pepper.
Let cool down and process half of the mixture in the blender until smooth. Put all back together.
Meanwhile in a separate skillet sauté mushrooms with 2 tablespoons olive oil over high heat until slightly brown, season with salt, pepper, and add to butternut mixture.
Cook pasta according to package directions, drain and toss with sauce.
Finish with cheese, parsley and remaining olive oil.
