Thoroughly rinse raspberries under running water.
Place berries in the top of a double boiler. Place water in the bottom of the double boiler and bring it to a boil. Cover and steam the fruit for 15 or 20 minutes or until it is soft and a thermometer placed in the fruit mixture registers 160 F.
Place the cooked fruit in a blender. Add ½ teaspoon of ascorbic acid crystals or 2 tablespoons of lemon juice per 2 cups of fruit. If desired, add 1 to 2 tablespoons of honey.
Drying time will vary depending on the equipment, moisture content of the fruit leather and the humidity in the air.
Spread puree evenly onto the sprayed drying tray, about ¼inch thick. Fruit leather may be dried in an oven or food dehydrator. Be sure the fruit has dried sufficiently or it will become moldy during storage.Properly dried fruit leather will be slightly tacky to the touch, but it should peel easily from the plastic wrap or tray. Test for dryness by touching the leather in several places; no indentations should be evident. Lift the edge of the leather, which will adhere tightly to the surface, and peel it back about an inch. If it peels readily, it is properly dried. If the leather cracks or chips, it has dried too long, but it still is edible.
After loosening the edge of the leather from the plastic wrap or pan, loosely roll the leather in plastic wrap or waxed paper in one piece.Store the roll in one piece or cut it into strips. Place the strips or rolls of leather in a plastic bag, glass container or other container. Store fruit leather in a cool, dry, dark place. It will retain good quality for up to one year in the freezer, several months in the refrigerator or one to two months at room temperature.