Cook pasta according to package instructions in salted water.
Meanwhile, add the oil, tomatoes, red onion, garlic, and butter to a large skillet and sauté over medium heat.
Once tomatoes and onions are tender, season with the salt, pepper, and pepper flakes.
Add the leftover pasta water, cream, and the boursin cheese to the pan, and stir to combine.
Add the pasta to the pan and stir to combine.
Garnish the pasta with fresh basil and grated parmesan cheese.
Serve and enjoy, friends.