For pickling liquid, in a small saucepan combine vinegar, water, sugar, and the 1/4 teaspoon salt. Bring to boiling; reduce heat and boil gently, uncovered, for 5 minutes.

Cut tomatoes into 1/4-inch-thick slices. In a large saucepan cook tomatoes and the 1 teaspoon salt, covered, in a small amount of boiling water for 1 minute. Drain; rinse with cold water. Drain well; transfer to three hot, clean half-pint jars. In each jar, place 1 teaspoon of the dill seed and, if desired, 1 or 2 serrano peppers. Pour hot pickling liquid over tomatoes, leaving a 1/4-inch headspace. Seal and refrigerate overnight or up to 2 weeks. Makes 3 half-pint jars.

Hot peppers contain volatile oils that can burn eyes, lips, and sensitive skin. Please wear plastic gloves while working with peppers and be sure to wash your hands thoroughly afterward.