In a large mixing bowl, add the potatoes, a pinch of salt and pepper and 1-2 tablespoons of olive oil. Toss to evenly incorporate ingredients.
Add the potatoes to the griddle and cook for 4-5 minutes, tossing often.
Reduce the heat of your griddle to low and add the garlic and rosemary and toss to incorporate. Cover with a dome and cook for another 4-5 minutes.
Add the butter and toss all ingredients together. Cover with a dome and cook another 4-5 minutes. When the potatoes are fully cooked, remove and serve hot.