Bring a large pot of salted water to a boil. Add the pasta and cook according to package instructions until al dente. Reserve ½ cup of pasta water, then drain the pasta in a colander.

In a large skillet, heat the olive oil over medium heat. Add the diced bacon and cook until crispy, about 5 minutes. Remove the bacon from the skillet using a slotted spoon and set aside, leaving the bacon fat in the pan.

In the same skillet, add the chopped onion and sauté for about 3 minutes, until it becomes translucent. Stir in the minced garlic and sliced mushrooms. Cook for an additional 5 minutes until the mushrooms are browned and tender.

Lower the heat to medium-low and pour in the heavy cream, stirring to combine. Let it simmer for 2-3 minutes until slightly thickened.

Add the grated Parmesan cheese to the sauce and stir until melted and smooth. If the sauce is too thick, add a little reserved pasta water to reach the desired consistency.

Season the sauce with salt and pepper to taste. Add the cooked pasta and crispy bacon to the skillet, tossing to coat the pasta evenly with the creamy sauce.

Serve the pasta in bowls, garnished with fresh parsley.