Scrub the potatoes clean. Pat them dry. Drop them in a pot of boiling water and cook them for about 12 to 15 minutes. They should be parboiled now. Don’t let them boil till soft. They should still be hard enough to slice through thinly.
Place one potato in a wooden spoon, tablespoon or dessertspoon. Hold the potato and the spoon together. With a sharp knife, slice the potato as thinly as you can. Repeat with the other three potatoes. The idea is to slice the potatoes almost to the bottom without cutting through. Place the sliced potatoes in a baking tray.
Put the butter, oil and garlic paste in a small pan. Heat until the butter has melted. Generously brush the oil-butter mixture all over the potatoes, making sure it gets in between the sliced portions.
Bake the potatoes at 225C (440F) for about 30 minutes. Generously brush the potatoes again with remaining oil-butter mixture. Season generously with salt and pepper. Sprinkle the minced herbs, if using, evenly over the potatoes. Return the potatoes to the oven, turning the tray around, and bake for another 30 to 35 minutes till crisp and golden brown.