[omk3]

I'm late to the party and I'm afraid there's no cake left.
Imagining there's still cake though, I would do it like this:

Spoiler:

Use two cuts to carve a cross on the cake, cutting it into 4 equal pieces.
Stack the 4 pieces on top of each other, and cut the whole stack in two with one cut.
I now have 8 equal pieces.

Where's the next puzzle, then?