In a high speed blender, blend San Marzano tomatoes until a liquid forms and no seeds remain.
Heat olive oil in a pot on medium heat. Make sure that it is olive oil and not extra virgin olive oil (see why here). Add onions. Cook until fragrant.
Once the onions start changing color, add the garlic. Cook for 30 seconds to 1 minute.
Add blended tomatoes. Bring to a boil and then simmer for 1 hour.
Add sugar, salt and pepper to taste.
Add basil and spices when there is about five minutes left. You can sub fresh basil for 1-2 tsp of dried basil or Italian seasoning.
