LDS scholars have a real answer here. Say so before your friend does.
God the Father and Jesus Christ appearing to Joseph Smith in a grove of trees. Everything else rests on it.
At least four times in his own lifetime, and the accounts differ. The 1832 one is in his own handwriting.
It describes one person, not two. It gives his age as about fifteen or sixteen.
And it says he had already decided the churches were wrong before he prayed. The 1838 account — the one now in scripture — has two persons and a different order of events.
The church's own Gospel Topics essay acknowledges all the accounts. It argues the differences reflect audience, purpose and memory rather than invention: the 1832 telling is about personal forgiveness, the 1838 about which church to join.
Genuinely arguable. People do retell formative experiences differently.
What is harder is that the number of persons present changes, and that most members never heard there was more than one account.
"Have you read the 1832 account in his own hand? The church published it."


Retellings shift with audience and purpose, and the church now publishes all four accounts.
The church's Gospel Topics essay acknowledges all the accounts. It argues that the differences reflect audience, purpose and memory, rather than invention.
The 1832 account stresses personal forgiveness. The 1838 account stresses the founding of the church. Retellings that grow in detail are normal when a person tells his own story many times.
Historians such as Milton Backman and James Allen argue that the accounts fit together. 'The Lord' in 1832 can cover two persons. And several tellings with shifting emphasis point to a real core experience, rather than a story being built up.
Arguable both ways. The sharp point is that one person in 1832 became two.
The accounts and their differences are plain fact from the sources. The church itself now prints them.
What is argued is whether the differences are ordinary shifts of memory, or a story that grew. The sharpest of them are one person against two. And a search for forgiveness against a question about which church is true.
Trained historians argue both readings.