Pierce each potato with a skewer 7–8 times while keeping the skin intact.

Wrap each potato in a damp paper towel, then cover with plastic wrap.

Arrange the wrapped potatoes around the edge of a microwave-safe plate and heat at 600W for 6–7 minutes.

Remove the plate and let the potatoes cool until safe to handle. Peel the skin off using the paper towel.

Cut the potatoes into bite-sized pieces and remove any sprouts.

Use a knife to break apart the mentaiko filling.