Place 2 bacon slices in vertical row on work surface, with short ends of slices slightly overlapping. Top with 1/6 of the potato slices, with curved edges of slices slightly overlapping and straight sides of potatoes even with one long side of bacon slices. Roll up, starting at one short end to resemble rose. Secure with wooden toothpick. Place in muffin pan cup sprayed with cooking spray. Repeat with remaining potato and bacon slices; cover.