My advisor recommended I email a well-known professor at another institution because of our shared interests.
He said I should use his name in my email so I'm good on that.
I (of course) refer to professors in my department and other professors who I have met by their first name. But having never met this particular person I am wondering what the least awkward least offensive most professional salutation would be in an email to hopefully set up a meeting.
Dear Prof. <Name>
-- because you don't know the professor personally, you are writing a total stranger, and should write accordingly.