Cut potatoes into bite-sized pieces, soak in water for 5 minutes, then drain. Place in a microwave-safe container, cover with plastic wrap, and microwave at 600W for 6 minutes.

Mash the potatoes in a bowl, then mix in potato starch, salt, pepper, and milk.

Cut cheese into 9 equal pieces, wrap each piece with the potato mixture, and form into balls.

Mix egg, flour, and water in a container until smooth. Coat the potato balls with the mixture, then cover with breadcrumbs.