Bring a large pot of salted water to a boil and cook pasta according to package instructions until al dente.
Meanwhile, heat olive oil and butter in a large skillet over medium-high heat.
Add sliced mushrooms and sauté until browned and moisture has evaporated, about 8 to 10 minutes.
Add minced garlic and cook for 1 minute until fragrant.
Pour in the heavy cream and simmer for 3 to 5 minutes until the sauce thickens slightly.
Stir in the grated parmesan cheese until melted and smooth.
Reserve 1/2 cup of pasta water, then drain the pasta.
Toss the pasta with the mushroom sauce, adding reserved water if needed for consistency.
Season with salt, pepper, and garnish with fresh parsley.