Heat a large pot with olive oil. Add garlic and onion and sauté for a few minutes until translucent and fragrant.
Add diced tomatoes and Italian herbs. Bring to a boil, reduce heat, pop on the lid, and let it simmer for 20 minutes. Take off the lid and let it simmer for another 10 minutes, so that excess liquid can evaporate.
Season with salt, sugar, and black pepper. Stir in basil leaves. Optional: Stir in 1-2 tablespoons tomato paste for a slightly thicker and more aromatic tomato sauce.
Notes
Can be served with pasta or as pizza sauce. To make it last longer, can it or freeze in portions.