Step 1

Gently cook the onion, carrot, celery, and parsley: Heat olive oil in a large wide skillet on medium heat. Add the chopped onion, carrot, celery and parsley. Stir to coat.Reduce the heat to low, cover the skillet and cook for 15 to 20 minutes, stirring occasionally until the vegetables are softened and cooked through.

Step 2

Add garlic: Remove cover and add the minced garlic. Increase the heat to medium high. Cook for garlic for 30 seconds.

Step 3

Add tomatoes, tomato paste, basil, salt, pepper, then simmer: Add the tomatoes, including the juice and shredding them with your fingers if you are using canned whole tomatoes. Add the tomato paste and the basil. Season with salt and pepper to taste.Bring to a low simmer, reduce the heat to low and cook, uncovered until thickened, about 15 minutes.Optional, purée for smooth sauce: If you want you can push the sauce through a food mill, or purée it in a blender or with an immersion blender, to give it a smooth consistency.