Can persimmons be pureed in a blender with the skin? I want to make a cake.

The skin of the Persimmon has many types of organic WAXES!, the list of waxes was put on a report and is available to view if you search for "Persimmon Analysis".

You won't want the skin in your cake. You can kind of turn them inside out and get the pulp out pretty easily.

Are they fuyu or hachiya? If hachiya, they have to be so soft I generally just squeeze the pulp out of the skin.

The skin is astringent and not something I would include in a cake. Your call though.