Heat oil in a 10-inch cast-iron skillet over medium heat.

Add half of the potatoes, cut side down.

Fry until golden brown, 4 to 6 minutes.

Flip potatoes and continue frying until skin is crisp and brown.

With a slotted spoon, transfer potatoes to a paper towel-lined baking sheet.

Repeat with remaining potatoes.

Carefully drain off all but 1 tablespoon oil.

Return pan to medium heat.

Add butter, garlic, and herbs.

Cook until garlic is fragrant and butter foams, 2 to 3 minutes.

Return potatoes to pan and toss to coat with garlic-herb butter.

Season to taste with salt and pepper before serving.