Place the tomato skins in a single layer on a parchment paper-lined baking sheet pan.
Once all the skins have been placed on a parchment paper-lined baking sheet pan, put the pan on an oven rack.
Set the oven temperature to its lowest setting.
The lowest setting of your oven will determine how long it will take to dry the tomato skins. The warmer the oven, the faster the tomato skins will dry. Drying time may vary from 2-5 hours.
Watch the drying process closely. If any of the tomato skins begin to stick to the parchment paper, loosen them.
Periodically during the drying time, shake the pans to redistribute the tomato skins to make sure they dry evenly.
Once the tomato skins have dried to a crisp, move on to the next step to make your tomato powder. But before starting the grinding process, make sure the skins are completely dry.