Directions

1. Prepare an ice-water bath; set aside. Bring a large stockpot of water to a boil. Score an X in the bottom of each tomato. Boil tomatoes in batches until skins begin to split, 1 to 2 minutes. Transfer to the ice-water bath; let cool slightly. Peel, core, and halve tomatoes. Working over a sieve set in a bowl, remove seeds. Discard seeds, and reserve juice.
2. Add lemon juice, if using (see note above), 1 teaspoon salt, and 2 basil leaves to each of 6 hot, sterilized 1-quart jars. Fill jars with tomatoes, cut sides down, compressing with a rubber spatula to remove air bubbles. Add reserved juice, leaving 1/2 inch space in each jar's neck. Wipe rims of jars with a clean, damp cloth; cover tightly with sterilized lids and screw tops. Transfer jars, using tongs or jar clamp, to the rack of a large canning pot filled with hot water; cover with water by 2 inches. (Jars should be spaced 1 inch apart, and should not touch sides of pot.) Cover; bring to a boil. Process jars in gently boiling water for 45 minutes. Transfer to a wire rack; let cool 24 hours. Press down on each lid. If lid pops back, it is not sealed; refrigerate unsealed jars immediately, and use within 2 weeks. Sealed jars can be store din a cool, dark place up to 1 year.