Wash tomatoes. Remove skins (see tip, page 000), stem ends, cores, and seeds. Finely chop tomatoes. Measure 3 1/2 cups. Place chopped tomato in a 6- or 8-quart kettle or pot. Heat to boiling; reduce heat. Simmer, covered, for 10 minutes. Measure 3 1/3 cups; return to the kettle.Advertisement
Add lemon juice and basil. Combine 1/4 cup of the sugar with the pectin; stir into tomato mixture. Heat to a full rolling boil, stirring constantly. Stir in the remaining 2 3/4 cup sugar. Return mixture to a full rolling boil. Boil hard for 1 minute, stirring constantly. Remove from heat. Quickly skim off foam with a metal spoon.
Immediately ladle hot jam into hot, sterilized half-pint canning jars, leaving a 1/4-inch headspace. Wipe jar rims; adjust lids.
Process filled jars in a boiling-water canner for 5 minutes (start timing when water returns to boil). Remove jars from canner; cool on wire racks.