I do this now as a side to my day job flying twin turboprops.
You will need the PA46 Type Rating on your EASA licence. If you are flying for reward you will need a FULL FAA CPL with IR. Depending on the particular aircrafts limits on altitude will determine if you need an FAA High altitude endorsement. Most of them are cleared above 25,000ft so you will do. You will also need a complex/high performance aircraft endorsement.
Most insurance companies require 50hrs dual time before allowing a new pilot to go solo. I do quite a bit of RHS time for this purpose.
I assume when you at you have and FAA PPL which is a 61.75 that allows you to fly IFR you have either done a full FAA IR or have done the IFP exams and an IPC? If not then you have a vanilla VFR PPL. It will say on the certificate the class such as SE land and then Instrument if you do.