1 (28-oz.) can whole peeled tomatoes
5 tbsp butter
1 onion, cut in half
2 sprigs basil
2 garlic cloves, peeled and crushed
1/2 tsp crushed red pepper flakes
Combine everything, including a pinch of salt, in a saucepan. Simmer over medium heat, stirring occasionally and breaking up the tomatoes, for about 45 minutes, until it reaches the consistency of pasta sauce. Remove the onion, basil, and garlic and serve with spaghetti.