Preheat oven to 425°F (220°C).
Wash and dry the potatoes. Slice thinly, about 1 cm apart, without cutting all the way through.
In a small bowl, combine melted butter, minced garlic, and rosemary.
Spray your baking dish and arrange the potatoes in a single layer. Brush generously with the garlic butter mixture, getting between each slice.
Roast for 45–55 minutes, brushing with butter halfway through, until golden and crisp.
Sprinkle with sea salt and fresh parsley before serving.