Put the spaghetti, oil, tomato paste, garlic, tomatoes, basil, crushed red pepper 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 (the sauce will thicken more), and season with salt if needed.
Divide the spaghetti among 4 bowls, and garnish with more Parmesan and torn basil leaves.
