Donuts exist in Runeterra....

Zoe and her Donuts do not come from Runeterra

They come from the Real Targon

So do Ice-creams. Whats so much of a shock here?

Donuts, Tacos, where's the pizza at?

Actually, that's not confirmed. Looking at her ability to travel through space and probably dimensions, it could be that she learned about donuts from another universe.

https://pm1.narvii.com/6629/5a53c522aeb7bbd6a35d9f0ae059aff5cb1422fc_hq.jpg

The most important lore reveal of all time.

This comes right next to Kled confirming tacos.

I mean they're a basic dessert like cake.