From WSJ. Uses fresh tomatoes, but doesn't remove seeds. Recipe says to cook it additional 10 minutes to make pizza sauce.
Ingredients
6 pounds ripe tomatoes
2 tablespoons extra-virgin olive oil
1 medium onion, chopped
1 ½ teaspoons salt
2 cloves garlic, finely chopped
¾ teaspoon freshly ground black pepper
¼ teaspoon dried red chile flakes (optional)
Instructions
1. Cut tomatoes in half or quarters. In a blender, purée tomatoes in batches until smooth.
2. Heat oil in a medium heavy saucepan over medium-high heat. Once oil is hot, add onions and salt and cook, stirring occasionally, until just starting to color, about 5 minutes. Stir in garlic and cook, stirring, until fragrant, 1-2 minutes. Add puréed tomatoes, pepper and chile flakes, if using, and bring to a boil. Cook until onions are falling-apart tender, 30-40 minutes.
3. Transfer sauce to blender and purée once more until smooth.