Prepare the flavour base - Heat olive oil in a large saucepan over medium heat. Add the diced onion and cook for 5–7 minutes until softened and slightly golden.
Add the garlic and tomato paste - Add the minced garlic and cook for 30 seconds until fragrant. Stir through the tomato paste and cook for another minute to deepen the flavour.
Add the tomatoes and seasonings - Add the crushed tomatoes, dried oregano, dried basil, sugar (if using), salt, and pepper. Stir well to combine.
Simmer the sauce - Reduce the heat to low and simmer uncovered for 35–45 minutes, stirring occasionally, until the sauce thickens and the flavours develop.
Adjust the texture - For a smooth sauce, use a stick blender to blend until your preferred consistency. Leave it slightly chunky for a more rustic homemade style.
Serve or store - Serve warm with pasta, use as a base for pizza or pasta bakes, or allow to cool completely before storing in the fridge or freezer.
