Modern-day revival of mint.
The long, burdening, inherent length of the phrase truly shows the user's approval of what/who he/she is directing the phrase at because it rejects the laziness and ease of staccato approval words such as "cool", or, "favorite."
Abbey: You guys are just the cookies and cream!
Abbey: I'm so cool.
Jake: The cookiest and creamiest, if I may say so myself.
Jake: What's your favorite ice cream?
Joe: Cookies and cream.
Jake: That's cookies and cream!
Joe: I know, that's what I said; cookies and cream.
Jake: Cookies and cream!
Joe: Stop it.
Jake: ....cookies and cream?
Joe: You're fired.
2. The swampy substance created by cumming on a girl's back after doggystyle sex and using the cum pool as an ash tray
Angie, the curves of your back make a fine vessel for the cookies and cream I've just deposited.
The result appears to be delicious cookies and cream on your partners lips.
mmmmmmmmm mmm good.