What is the simplest op amp level shifter?
You can't have a single op-amp configured as a non-inverting level shifter (with no gain) because with no-gain the non-inverting input is at the same potential as the output thus preventing the ability to create an offset. You could achieve this with two op-amp circuits cascaded but, simplicity has gone out of the window. You could have gain and get a non-inverting level shifter but then you'd have to reduce the gain afterwards.

I don't think the questioner may appreciate this - questioner to comment?