Wash and drain the tomatoes and fresh basil.
Peel the onion and garlic.
Place most of the ingredients in a food processor and blend until smooth.
You may need to dice the onion and mash the garlic before to make sure there are no large pieces left.
If you prefer a chunky texture, leave some tomatoes and basil aside, dice and add to the smooth sauce.
When done, place in an airtight container and store in the fridge for up to a week.
To keep it fresh for longer, pour a thin layer of extra virgin olive oil on top and store for up to 2 weeks.
Marinara sauce is perfect as topping on low-carb pizza!