The quantity of sauce this makes is ideal for 750g of anything, but if you prefer less, just put less sauce in whatever you're making, if you prefer more, I would double all ingredients for ease. You can always freeze the excess.*

Fry the onion over a low heat for 5 minutes or until translucent, stirring regularly.
Add the garlic and cook for a few seconds more.

Add the tomatoes, sugar (optional) and herbs (optional) and cook for 5 minutes, stirring regularly.
Add a splash of water if necessary to loosen the sauce and season to taste.