Preheat oven to 400°F (200°C).

Scrub and dry the potatoes.

Lay potatoes flat and make thin, parallel slices about 1/8 to 1/4 inch apart, going about 3/4 of the way through the potato.

Lightly coat the potatoes in olive oil.

Season the outside and between each slice with salt.

Wedge a thin slice of butter between every few slices.

Place a small piece of thyme (stem end inserted) between the alternate slices.

If omitting butter, ensure each slice is well-coated with olive oil.

Bake in the center rack of the preheated oven for about 1 hour, or until potatoes are fork-tender and crispy on the outside.

Discard thyme stems.

Drizzle with melted butter or olive oil.

Sprinkle with chunky salt.

Serve immediately and enjoy.