Oven-dried tomatoes provide the same strong flavor and texture as sun-dried tomatoes, but they dry much more quickly in the controlled heat of your oven. Dried tomatoes boost the flavor of sauces, soups and vinaigrettes. The concentrated flavor in a dried tomato means that a little goes a long way, so you may not need to use as many tomatoes to get the same flavor quality as you would with fresh.
Line the bottom oven rack with aluminum foil to catch any drips. Alternatively, place a large cookie sheet on the bottom rack to catch drips.
Preheat the oven to 140 degrees Fahrenheit, propping the oven door slightly ajar so air can circulate. Place an oven thermometer inside the oven and adjust the temperature as needed so it remains at 140 F even with the door open.
Wash the tomatoes and slice out the core. Cut smaller tomatoes in half and cut large tomatoes into quarters. Scoop the pulp and seeds from each half and discard it.
Arrange the tomatoes in a single layer, skin-side down, on an oven-safe cooking rack. Leave 1 to 2 inches of space between the tomatoes so air can circulate freely. Sprinkle the tomatoes with salt to taste.
Place the tomatoes in the oven. Rotate the tray every one to two hours so the tomatoes dry evenly. Press on the top of the tomatoes with a spatula if they begin to curl, usually about halfway through the drying time. Depending on humidity in the kitchen and the juiciness of the tomatoes, it can take as little as six hours or as long as 18 hours for the tomatoes to dry completely.
Remove the tomatoes from the oven when the edges feel dry and sharp and when the rest of the tomato feels dry but leathery. Cool to room temperature and then package the tomatoes in an airtight jar or storage bag.
Store oven-dried tomatoes in the refrigerator or freezer for up to one year. Cold storage prevents discoloration and flavor changes, helping to extend the shelf life of the dried tomatoes.
If you prefer skinless tomatoes, such as for stewing, cut an “X” in the bottom of a whole tomato and dip it in boiling water for 20 to 30 seconds, and then immediately cool it in ice water. The skin will slip off and then you can cut and seed it for drying.
Rehydrate tomatoes in boiling water, such as adding them to a slow-cooking soup or stew. Alternatively, soak the tomatoes in hot water for 30 minutes and use them as sun-dried tomatoes.