Step 1

Preheat the oven to 150ºF. Line a rimmed 12½ by 17¼-inch (half- sheetpan with a silicone baking mat.

Step 2

In a blender or food processor, blend the mango until smooth. Transfer the mango to a bowl and set it aside. Add the raspberries and sugar to the blender and blend until smooth. (It is important to blend the raspberries with the sugar, as the sugar helps liquefy the berries.)

Step 3

Place dollops of the mango and raspberry purées on the prepared pan. With a small offset spatula, spread the purées evenly over the pan—try to spread them as evenly as possible, not too thin and not too thick, and try not to spread them to the very edges, so you’ll have room to grab the fruit leather and peel it off the mat when it’s cool.

Step 4

Bake for 2 hours 30 minutes to 3 hours, rotating the baking sheet every hour. The leather is done when it is still tacky but not too sticky or wet. Let the leather cool.

Step 5

Remove it from the mat and place it on top of a sheet of wax paper. Cut the leather and wax paper into strips with scissors and roll them up paper-side out, then store them in a sealed container at room temperature for up to 1 week.