Bring a large pot of water to a boil over high heat. Add the pasta and continue to boil until tender (7-10 minutes). Drain the pasta.
While the pasta is cooking, prepare the creamy tomato sauce. Dice the onion and mince the garlic. Add the onion, garlic, and olive oil to a large skillet and sauté over medium heat until the onions are soft and translucent (3-5 minutes).
Add the diced tomatoes (with juices), oregano, basil, crushed red pepper, salt, and some freshly cracked pepper to the skillet. Stir to combine. Add the tomato paste and a 1/2 cup of water to the skillet and stir until the tomato paste has mixed into the sauce.
Turn the heat to low. Cut the cream cheese into a few pieces and then add them to the skillet with the tomato sauce. Use a whisk to stir the sauce until the cream cheese has fully melted and the sauce is creamy. Add the Parmesan to the skillet and stir until it is melted into the sauce.
Add the fresh spinach to the skillet and gently stir it into the sauce until it has wilted (2-3 minutes). Add the pasta and stir until it is well coated in the creamy tomato sauce. Taste and adjust the salt and pepper as needed. Serve warm.