Wash the potatoes very well, dry and slice them without cutting the bottom.
Sprinkle salt and oregano, put thinly sliced cheddar cheese and butter in 3-4 places. Save the cheddar slices for topping as well.
Put foil on a baking mold, grease it with oil and place the potatoes. Cover the top with foil and put it in the oven heated to 240 °C, after 30 minutes, remove the foil, arrange the remaining pieces of cheddar on the potatoes and bake again until the potatoes are cooked.Bon Appetit!