Plasterboard protruding

[Snowyy]

Door for utility has no archatrave framing and it is flush with the plasterboards one side however not on the other, pic below showing what it looks like, what would be best way to sort this? Maybe sande it to a chamfer or would it be better to cut some of it away so that I can fit some framing-although with the adjoing wall being at an angle would that give me a problem? Any advise please greatly appretiated.

 

[Swwils]

Cut down and introduce a splay angled bead.

Then make it back up.

 

[mrrusty]

It's one of the jobs multitools were made for. Really easy to trim the plasterboard back so the architrave can fit flush.