Heat the olive oil over medium heat. Add the onion and cook for 4-6 minutes until becoming translucent. Add the garlic and mushrooms and cook for 3-4 minutes. Add the tomatoes with juice, tomato paste, and red pepper flakes. Stir in the cream cheese and Parmesan. Stir to create a creamy sauce. Add the pasta water as needed to thin out the sauce, start with 1-2 tbsp. and add as needed.