Stories We Like: A Guide to the Comma
by 1952, "display of male pulchritude" in movies or magazines; said to have been modeled on cheesecake, but there seems to have been an actual foodstuff called beefcake around this time. The word seems to be little used in that literal sense since the other sense emerged.
A photograph or photographs of a muscular male body with little or no clothing; a muscular handsome man: The actor has no objections to male cheesecake, or beefcake as it is called in Hollywood
[1940s+; based on cheesecake]