Process chopped tomatoes in a food processor for a smoother texture or use crushed tomatoes or passata. (Alternatively you can skip this step for a chunky spaghetti sauce.)
In a large pot heat the olive oil over low heat, add minced garlic and chopped basil and stir for no longer than 10-20 seconds. Do not let them burn or they will turn bitter.
Add tomatoes, dried oregano and salt, bring to a boil and let it simmer over very low heat for 7-10 minutes.
Cool and store in a clean jar or divide and freeze for a later use.