Peel the potatoes and make cuts perpendicular to their long side, but not all the way through. You have to get a fan-like arrangement.
Arrange them in a tray, sprinkle with salt, powdered garlic and oil but be sure to get them in between the individual slices. Also place a slice of firm cheese in between each of the slices.
Sprinkle black pepper, pour a little water into the tray and cover with aluminum foil.
Once they're baked, remove the foil and sprinkle grated cheddar on top.
Return for about 5 min. to the oven.