This one-pot meal is perfect for the beginner cook: Everything but the cheese goes into one skillet, and it all magically comes together. The tomato paste is here for a little flavor insurance, just in case your tomatoes aren’t at their best. Feel free to add an extra tablespoon when they’re out of season.
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 (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.