Wash and core fruit. Fruit may be pureed with or without the skin. The skin on red apples will give the puree a nice pink to reddish color. Place pieces of fruit in blender. Puree until smooth.
Some fruits make a smoother puree if they are cooked first with a little water, then pureed.
When the puree is smooth, pour onto the prepared cookie sheet. Leave at least 1 inch around the edges so that the puree has room to spread and the plastic wrap can be removed easily. The center should not be sticky. Remove the leather from the tray while it is still warm. Peel away the plastic wrap and roll up the leather.