A question about Birdo's huge eyes

Hello! A long time follower here with a quick question.

I'm in the process of making a Birdo fursuit, but I'm in a bit of a pickle. I have no clue how to make those giant eyes!





One of the best refs I can find. Birdo's eyes are huge!



And here's the idea of the suit I'll be making. I'm not worried about the body just yet; I'll be wearing a partial at Otakon.

So what do you think? A friend suggested that I'd make them out of giant foam Easter eggs; like the hollow ones you see in Michaels during the Spring. Does anyone have any other suggestions?

Thanks!