Note: We developed this recipe using ripe in-season tomatoes. Supermarket vine-ripened tomatoes will work here, but the sauce won't be as flavorful. Don't use plum tomatoes; they are low in moisture and don't work well in this recipe. This is a light-bodied sauce, so don't adjust its consistency with reserved pasta cooking water as you would with most other pasta sauces or it will be too runny. This recipe can easily be doubled.

Cut tomatoes in half along equator. Set fine-mesh strainer over medium bowl. Gently squeeze tomato halves, cut sides down, over strainer to collect seeds and jelly, scraping any seeds that cling to tomatoes into strainer. Using rubber spatula, press on seeds to extract as much liquid as possible. Discard seeds. Set aside 1 cup liquid and transfer any remaining liquid to large bowl.

Cut tomatoes into rough 1½-inch pieces. Working in 2 or 3 batches, process tomatoes in blender until smooth, 30 to 45 seconds; transfer puree to large bowl with strained liquid (you should have about 10 cups puree).

Heat 2 tablespoons oil in Dutch oven over medium heat until shimmering. Add garlic, pepper flakes, and oregano and cook until fragrant, about 1 minute. Stir in tomato puree and 1 teaspoon salt. Increase heat to medium-high and bring to simmer. Reduce heat to medium-low and simmer, stirring occasionally, until reduced to 4 cups, 45 minutes to 1 hour.

Remove pot from heat and stir in basil, reserved tomato liquid, and remaining 2 tablespoons oil. Season with salt to taste. Use immediately or let cool completely before refrigerating or freezing. (Sauce can be refrigerated for up to 1 week or frozen for up to 3 months.)