Freeze shirasu by placing it on a lined aluminum tray and freezing for 45 minutes. Transfer to a freezer bag for storage.

Slice potatoes thinly and soak in water. Drain well.

Place potatoes and 2 tbsp water in a microwave-safe dish, cover loosely with plastic wrap, and microwave at 600W for 5 minutes.

Heat olive oil in a pan, spread half the cheese (30g), and layer potatoes on top. Sprinkle with salt and pepper, add remaining cheese (30g), and top with frozen shirasu.

Cook on medium heat until sizzling, cover with a lid, and cook on low heat for 2–3 minutes until cheese melts. Remove lid and cook on medium heat until cheese is crispy.