Sun-dried tomatoes can be made in the oven using 2 pounds of plum tomatoes that are cut lengthwise. Place the cut side up on a baking sheet, and season with salt. Let the tomatoes stand for 20 minutes. Roast in a 250 degrees Fahrenheit oven for about four hours, until the tomatoes are slightly dry but still have juice. Drizzle them with olive oil, and sprinkle with thyme.
Sun-dried tomatoes can also be made using a dehydrator. Use 7 to 8 pounds of firm plum tomatoes that have been stemmed with the hard core removed. Cut the tomatoes in half lengthwise, and scrape out the seeds without removing the pulp. Mix 1 teaspoon each of basil, oregano and thyme with 2 teaspoons salt. Sprinkle a small amount of this mixture on each tomato. Place the tomatoes cut side up on a dehydrator tray, and set the temperature to 140 degrees Fahrenheit. Turn the tomatoes over after four to five hours, and press them flat using a spatula. After a few hours, turn again, and flatten gently. Continue drying until done.
Sun-dried tomatoes may be made in advance and refrigerated. They should be brought to room temperature before serving. Commercially made sun-dried tomatoes spend up to 10 days in the sun for the drying process to be complete. Larger tomatoes lose up to 93 percent of their weight in the process. Sun-dried tomatoes are rich in lycopene, antioxidants and vitamin C.