My daughter the commedian

A conversation had while swinging last night.

Iz: I gotta joke.
Me: Ok, lets hear it.
Iz: Knock, Knock. Who's there?
Me: I don't know who's there?
Iz:Izzy's chocolate milk.
Me: Izzy's chocolate milk who?
Iz: Izzy's chocolate milk cookie.

Then we both fell apart into giggles. Later she told it as Addy and Mama's chocolate milk cookie. I believe the name is interchangeable so feel free to wow your friends and coworkers with that one.