Fill a large pot with water and bring to a boil. Add a generous pinch of salt and the spaghetti. Stir to break up the pieces and cook until al dente or according to package instructions. While spaghetti is cooking, coat your pan with the oil and sauté the chopped tomatoes, garlic and pepper flakes under medium-low heat for 5-10 minutes, or until the tomatoes start to break down. Add salt and fresh pepper and stir. Drain the pasta, reserving ½ cup of water for finishing if the sauce is too dry. Mix the hot spaghetti with the fresh tomato sauce and simmer for a minute or so. Turn the heat off, add basil, grated cheese or mascarpone and mix well. Serve immediately.