This cake was a smash cake and I would really like to do the same thing but not quite sure how to make those ruffles......certain tip???

Sorry the whole pic uploaded. I'm just looking at the pink smash cake. Can anyone help?? I love the looks of this but have never done the ruffles before! Please and thank you for your help!!! :)

definitely looks like fondant to me.

I made a video piping buttercream ruffles with the giant rose tip #127 D.

(I'd use a 124-127 for multiple layers of ruffles.)

http://s984.beta.photobucket.com/user/Unlimited1cakes/media/127Drufflecake.mp4.html
 

That's definitely buttercream...Just use a big petal tip and wiggle it in a wavy shape while piping. Start a the bottom and work your way up.

AI've seen that exact cake on Facebook and its done with fondant.