The first step is to preheat your flat top grill to high temperature.
Grab two bowls, one for steak and one for potatoes. Then cube up your steak, and potatoes. I did 1 inch cubes for steak pieces and then for potatoes I cubed in half to quarters depending on the size.
Then pour 1/2 teaspoon of oil in each of the boils. Along with 1/2 teaspoon salt in each, 1/2 teaspoon pepper, and split the 1/2 teaspoon of garlic powder between the two.
Toss with a spoon to coat all the potatoes in the steak and potatoes. Then head outside.
Add a little oil to one side of your Blackstone, and toss down the potatoes. Spread into a single layer. Squirt on some water, and cover with a dome, or 9x13 aluminum foil pan.
Let the potatoes cook for 4-5 minutes. Then remove the dome, stir well, squirt more water, and then cover again for another 4-5 minutes.
Add your butter and garlic into a small pan and place on the side of the grill to let it melt.
Toss down your steak, and sear on each side. You will cook the steak till your desired doneness. I made ours well done.
Remove the dome from the potatoes and stick a fork in to check the doneness of the potatoes. If the potatoes are done they will be fork tender. If you need repeat water and dome one more time. Or let them finish cooking witout the lid.
Once the steak and potatoes are cooked spoon some of the garlic butter mixture over the steak and potatoes. Stir to mix and then plate up the garlic butter steak, potatoes, and serve the rest of the garlic butter on the side.