Put the spaghetti, oil, tomato paste, garlic, tomatoes, basil, red pepper flakes and 1 teaspoon salt in a high-sided medium skillet. Add 5 cups water and bring to a boil over medium-high heat. Continue to cook, stirring the spaghetti frequently to keep it from clumping, until it is al dente and the sauce has reduced and thickened, 6 to 8 minutes. Stir in the Parmesan and cream cheese (the sauce will thicken more) and season with salt if needed. Top with more Parmesan and sliced and whole basil leaves.