the crust. put the zest and sugar into a food processor and process until the two are well combined and the zest has completely incorporated into the sugar. you will still see tiny specks of zest, but no big pieces. keep processing until you get to that stage. add the flour, and cold butter to the bowl...
, adding some applesauce or pear puree if the mixture is too runny and a little water or juice if the mixture is too thick. dehydrate fruit leathers continuously to ensure even drying all over. when dry, fruit leathers should be pliable with no soft spots, easy to roll up into logs when still warm from...