An easy izakaya appetizer. Use tarako (cod roe) instead of mentaiko (pollack roe) if you'd like.
I imitated something I saw on a shabu-shabu restaurant menu. It was just served without beint cut so it was hard to eat, so I asked one of the waiters to cut it up for me.
By removing the pith it's easier to place the mentaiko inside. If you don't take it out, then dry the cut side with a paper towel.The more mentaiko you use, the better this is.
Enjoy Japanese food around the world.