Step 1

Line a rimmed baking sheet with parchment paper; set aside. (Make sure it fits in your freezer, otherwise line 2 large plates instead.)

Step 2

Place the yogurt, sweetener, vanilla, and salt in a medium bowl and whisk to combine. Pour onto the baking sheet and use a rubber spatula to spread into an even layer about 1/2-inch thick (it will not reach to the edges of the baking sheet). Scatter the grapes and granola evenly over the yogurt.

Step 3

Freeze uncovered until solid, about 4 hours. Pick up the bark by grasping the parchment and lifting it up and onto a cutting board. Cut or break into irregular pieces and serve immediately, or keep frozen in an airtight container or freezer zip-top bag.