Recursion does do that by default respective to what the given function executes. No alteration or special convention is required. Loops that require use of syntax other than a function call are synchronous only.

If it would you can find me on IRC and I would be more than happy to show you how to program.

I see you've gone from recursion "can iterate asynchronously" to it "does do that by default".

In most languages, recursion is not asynchronous, even if it could be, which is part of the point I was making. I'm guessing English is not your first language.