It looks like the tubular egg that they use in cafeteria.

You’re not alone, I would totally see this at a hotel for breakfast 😁

Look again more carefully. The objectionable part isn’t actually the egg, it’s the granulated sugar coating.

Lots of other folks in this thread are (rightfully) pointing out that hard-boiled eggs can taste fine when baked into things, but all their examples are savory and this one isn’t.

It might not taste bad but I wouldn’t call it “cake”