Found this in the Wall Street Journal.

Locked in a safe.

And another disclosed location sets the key to the success of America's hottest chicken chain.

Oh, Kentucky Fried Chicken.

A list handled some 30 years ago by the co-founder of Raising Cain's Chicken Fingers.

Oh, Raising Cain.

Is the only physical copy of the recipe for the chain's famous milk shakes.

Milkshake.

Sorry, I've stepped on your joke.

View people have seen it.

And while copycat recipes and alleged leaks from disgruntled employees abound.

I wasn't a fan of the milkshake.

The company says those who have seen the list,

only those who have seen the list know how to make.

Raising Cains, milkshakes.

How do they make it in the stores?

With a lot of pride, care, and secrecy.

I believe there's a packet of seasoning that comes, it's already pre-mixed, that you don't need, just add that in, you don't know what it is exactly. Isn't that safe? Isn't KFC's recipe still a secret? I think so. The 13 original spices or what it is? Stuck in the coat of Curtis as he's in the grave. They get into that.

There's somebody else has some secret sauce, too.

Inside the safe, one of several security protocols,

from NDA agreements to unmarked ingredients packages

that raising Cain's employees protect the...

...