Line a rimmed baking sheet with aluminum foil (make sure it fits in your freezer, otherwise line two large plates instead); set aside.
In a medium bowl, whisk the yogurt with sugar until smooth. Pour onto the baking sheet and use a rubber spatula to spread into an even layer about 1/2-inch thick. You don’t want the yogurt mixture to touch the sides of the baking sheet.
In a small bowl, gently stir to combine the strawberries, pistachios, and maple syrup. Evenly scatter the mixture over the yogurt.
Freeze uncovered until solid, about 4 hours or overnight. Pick up the bark by grasping the foil and lifting it up and onto a cutting board. Break with a wooden rolling pin or carefully cut into serving pieces. Enjoy immediately or keep frozen in a resealable plastic bag.
Adding more sugar helps to create a creamier end-result.