Can’t remember where I found this online, but it is purported to be Ernest Hemingway’s own hamburger recipe.
A quick search turned up this article, which actually recreated the burger (with substitutions for unavailable ingredients): https://www.artofmanliness.com/living/food-drink/ernest-hemingways-favorite-hamburger/
This actually looks pretty darn awesome. I have never heard of mei yen powder, and it looks like it’s discontinued.
Here is a substitute recipe someone got from Spice Islands.
https://everything2.com/user/Venkman/writeups/Mei+Yen+seasoning