In a large skillet, heat the oil over medium heat for 30 seconds.
Add the onion and cook for 5 minutes, stirring occasionally.
Add the garlic and continue to cook for 1 minute.
Add the tomatoes and oregano and simmer for 20-25 minutes.
Break up the tomatoes using the back of a spoon until the sauce is just slightly chunky. If you want a smooth sauce, you can use an immersion blender to blend the sauce until you get your desired consistency.
Stir in fresh basil at the end of cooking.
