Heat the butter in a heavy-based saucepan.
Add the onion and garlic and sauté until onion is translucent.
Add the tomatoes, tomato paste, sugar and origanum.
Allow to simmer uncovered for 15 minutes or until mixture has thickened.
Stir in the basil.
The sauce can be made up to 2 days before using.
Cover and refrigerate. If a smoother sauce is needed, allow sauce to cool and blend with a stick blender until smooth.
This sauce can be frozen in an airtight container for up to 6 months.
Make a large batch and freeze for later use.