Bring a large pot of water to boil.
Add the potatoes once boiling and cook for 15-20 minutes, until tender.
Drain and let cool for a few minutes.
In a small bowl, melt the butter.
Stir in the garlic powder, salt, and Parmesan cheese.
Toss the butter mixture with the potatoes.
Heat the Blackstone to medium-high heat for 5 minutes to get it hot.
Drizzle with olive oil. Next, add the potatoes to the grill and smash using a burger press or the bottom of a glass cup. There will be extra butter left in the bowl - save it for later.
Cook the potatoes on the griddle for 4-5 minutes, until the bottoms are golden brown and the edges are crispy.
Flip, brush each potato with additional Parmesan butter, and cook another 4-5 minutes. You can sprinkle each one with more Parmesan cheese if needed.
Using a spatula, remove the smashed potatoes from the grill and transfer to serving platter.
Sprinkle with chives. Serve and enjoy!