Preheat your oven to 200°C (400°F).
Wash and peel 4 medium-sized potatoes (about 800 grams). Place each potato between two chopsticks or wooden spoons to prevent cutting all the way through. Carefully make thin, even slices along the width of the potato, about 3-4 mm apart.
In a small bowl, mix 50 grams of melted butter, 2 minced garlic cloves, 1 teaspoon of salt, and 1/2 teaspoon of black pepper. Brush the potatoes with half of the butter mixture, making sure to get it between the slices.
Place the potatoes on a baking tray lined with parchment paper. Bake for 30 minutes.
Remove the potatoes from the oven and brush them with the remaining butter mixture. Bake for an additional 30-40 minutes, or until the potatoes are golden brown and crispy on the outside, and tender on the inside.
Garnish with chopped fresh coriander or parsley and serve hot.