With a sharp knife or mandoline, slice the potatoes into ⅛"-thick pieces.
Brush the bottom of a 10" oven-safe fry pan with 1 tablespoon butter. Arrange the potato pieces in the pan vertically, but at a slight angle, in a circular pattern.
Brush top with remaining butter. Sprinkle with thyme, salt and chili flakes, if using.
Bake for 1 hour or until potatoes are tender and the edges are crispy. Let sit for 10 minutes before serving.
Recipe by Two of a Kind at http://www.twoofakindcooks.com/crispy-roasted-potatoes-thyme/