Preheat a grill over high heat. Oil the grates with nonstick cooking spray
You will need to roll the dough out on some sort of flat sheet without an edge on it, like a cookie sheet without a lip. Flour the cookie sheet and use a rolling pin to roll out to about ⅓" thickness. Shake your cookie sheet to make sure that the dough can easily slide around. If not, loosen, and add a bit more more flour under dough.
Turn the grill down to low heat. Use your cookie sheet to transfer the dough to your grill using a back-and-forth motion. Spray the surface of the dough with cooking spray. Allow dough to cook for 5 minutes, then flip using tongs, and continue grilling for 3-5 minutes, until slightly puffed up and cooked through. Slide cookie sheet underneath to remove.
Immediately spread with chocolate hazelnut spread and dot with berries. Sprinkle with powdered sugar, cut into pieces and serve.