In a wide pan, heat olive oil over medium-high heat. Add tomatoes and red pepper flakes and season lightly with salt and pepper. Let cook for a few minutes until tomatoes start to soften. Then using a potato masher, cup the tomatoes finely. Cook 20 to 25 minutes until sauce has thickened.
Yields about 3 cups. Refrigerate for up to 2 days or freeze.
For spaghetti, after cooking spaghetti just shy of “al dente,” reserve 1 cup pasta water. Drain pate, add to sauce and cook over medium-high heat, gently tossing the pasta and sauce together. If sauce and spaghetti is too think add a little pasta water.
Take off heat and toss in butter, cheese and basil. Serve immediately.