Steps
1. Cook the pasta in salted boiling water according to package instructions. Drain and set aside.
2. In a large pan, melt the butter and heat the olive oil over medium heat. Add the onions and garlic, and sauté until fragrant and translucent.
3. Add the mushrooms to the pan and cook until they release their moisture and become golden brown.
4. Pour in the heavy cream and simmer for a few minutes until it thickens slightly. Stir in the grated Parmesan cheese and season with salt and pepper.
5. Add the cooked pasta to the pan and toss to coat it evenly with the mushroom cream sauce.
6. Serve the creamy mushroom pasta hot, garnished with fresh parsley.