Preheat oven to 175 degrees F.
Blend or purée blueberries, raspberries, blackberries, and lemon juice (optional: you can strain for seedless strips).
Line baking sheet with silicone baking mat or parchment paper.
Pour mix onto baking sheet, spread evenly with spoon.
Bake 4-5 hours (if it’s sticky to touch or makes an indent with your finger it needs more time — shouldn’t be shiny, but if you overcook strips will be crunchy — different, but great for cereal and adding to smoothies!)
Cut into strips using pizza cutter.