Wash, remove stems and slice plum tomatoes in half lengthwise. Place skin side down on a wire rack and sprinkle with mixture of salt and sugar. Place rack on a cookie sheet in the oven and bake for 12 to 14 hours. They will shrivel, turn dark red, and the skins will toughen. Let cool and store in an airtight container in the freezer until ready to use.
These are great diced in salads, bean salads, on pizza and over vanilla frozen yoghurt.
