Preheat your oven to 170ºF (or the lowest setting – you just don’t want to go above 200ºF) and line a rimmed baking sheet with parchment paper.
Puree the peaches, raspberries, sugar, and lemon juice together using a traditional or emersion blender until very smooth. Transfer the fruit puree into a medium saucepan over medium heat and bring to a simmer. Turn the heat down to medium low and, stirring frequently, cook until very thick and jammy, about 30 to 35 minutes.
Transfer the cooked down puree onto the prepared baking sheet and spread into a thin and even layer. Bake in your preheated oven to dehydrate for three to four hours or until no longer jammy and just barely tacky.
Remove the baking sheet to a rack and allow to cool completely before peeling the fruit sheet off of the parchment*. Cut the sheet into ten long strips and roll up with a thin piece of parchment or wax paper. Store in a airtight container or zip top bag for up to one week.
*If the fruit sheet is still a bit jammy after removing from the parchment, return it to the low oven for 10 to 20 minutes or until tacky and firm.