Can I make the lemon posset with evaporated skim milk instead of heavy cream?

I haven't ever tried it with anything but heavy cream. Sorry!

I think you better stick to the heavy cream. If it's the fat content you're worried about, you could probably use half and half or cut the heavy cream with 2% or whole milk, but it's the evaporated bit about your idea that worries me. Eh, you only live once!