Peel the potatoes for mashing. Cut into small dice, rinse and place in a saucepan, and cover with cold water. Bring to the boil and simmer for 15-20 minutes until soft.
Drain well, and mash thoroughly. Allow to cool for a few minutes, then add the egg yolk and mix well. Set aside.
Meanwhile, scrub the small potatoes thoroughly and slice thinly. The slices should be no more than 2-3 mm (approx. ⅛ inch) thick.
Place the potato slices into a bowl with the olive oil, salt and pepper and mix thoroughly so that all the slices are coated in the oil.
Preheat the oven to 180°C (350°F).
Brush the inside of each of 10 holes in a 12-hole muffin tin with oil. Divide the mashed potato between the oiled holes.
Now, lay out about 10 slices of potato in a row, overlapping the slices. Start at one end and carefully roll them up, then push the rolled up sliced into the mashed potato in one of the holes. If necessary, arrange a few more slices around the edge to finish the 'rose'.
Repeat with the remaining slices to make 9 more roses.
Bake at 180°C (350°F) for around 45 minutes until cooked, golden and crispy. Serve at once!
