Wash the tomatoes thoroughly, then blanch them in boiling water for 1-2 minutes until the skins start to split. Remove and place in ice water to cool.

Peel the tomatoes, remove the cores, and chop them into quarters.

In a large pot, heat the olive oil over medium heat. Add the chopped onion and sauté until translucent, about 5 minutes.

Add the minced garlic and cook for an additional minute until fragrant.

Stir in the chopped tomatoes, salt, pepper, oregano, basil, and sugar. Bring to a simmer and cook uncovered for about 1.5 hours, stirring occasionally until thickened.

Using an immersion blender, blend the sauce to your desired consistency. Alternatively, transfer to a blender in batches.

Ladle the hot sauce into sterilized canning jars, leaving 1/2 inch headspace. Wipe the rims clean and seal with lids.

Process in a water bath canner for 35 minutes for pint jars or 45 minutes for quart jars.