The standard dessert for most transpacific as well as transatlantic flights in both regular economy and Premium Plus has been a "Milk Bar" cookie which is supposed to be served cold. This has replaced the mini ice cream or gelato cups for quite a while. There are several packages presently -- yellow, blue/cyan (hard to tell), and pink. In the referenced post above (#20 I believe) you can see the blue version on the tray.

The latest one that I had was a colorful "birthday cookies" version which is really quite good. I enjoyed it. Although ice cream and gelato are my favorites, these cookies are okay as they don't melt, and I don't have to eat them right away.