Although microwaves were designed to cook food quickly, the process of making sun-dried tomatoes using a microwave takes time and patience. There are many varieties of tomatoes to choose from; however, Roma tomatoes work best because they are meatier. The key to successfully making sun-dried tomatoes with a microwave is to maintain good air circulation, adjust the microwave to the proper power level and pay attention to the time intervals while turning the tomatoes.
Wash the tomatoes to remove any dirt or chemicals. Put 10 Roma tomatoes into a clean bowl with cool water. Gently rub each one with your hands and rinse them in cool running water. Dry the tomatoes with paper towels.
Place the tomatoes on a wood cutting board and cut each one in half lengthwise with a sharp knife. Hollow out each half by scooping out all the seeds and juice with a teaspoon. Use a paper towel to soak up any excess juice.
Put the tomato halves on a microwave dish with ribs, similar to a microwave bacon tray. This will keep the tomatoes off of a flat surface and promotes good air circulation. The grooves in the dish give the juice a place to drain away from the tomatoes. Be sure to set the tomatoes perpendicular to the ribs. Position them face up with a small space between them -- they should not touch each other. Sprinkle the tomatoes with an all-purpose seasoning.
Set the dish, uncovered, into the microwave. Adjust the microwave to cook at 20 per cent power or a power level of 2 if there are 10 levels. Set the timer to 45 minutes. At 15-minute intervals, turn the tomatoes over with a large serving spoon.
Adjust your microwave to cook at 10 per cent power or a power level of 1. Set the timer to five minutes. After five minutes, turn the tomatoes over with the serving spoon. Continue microwaving the tomatoes in five-minute intervals and turning them until they have dried. When dry, the tomatoes will be a little flexible, withered, and significantly smaller in size.
Take the dish out of the microwave and place each tomato onto a cooling rack. Allow them to sit for 30 minutes, undisturbed, to thoroughly cool.
Put the sun-dried tomatoes in a freezer bag and store in a refrigerator until you are ready to use them.