I love the gold sequin look (where you cover the cake in confetti sprinkles and paint them gold), but I've only seen it done on fondant covered cakes, and I'm curious to know if anyone has tried it on a buttercream cake? Thanks so much!

A post I made here last year:

We just had a demo of this at the OH ICES Day of Sharing yesterday.

The demonstrator used round, primary colored quins [sprinkles].  She pressed them into fresh buttercream.  She made a paint of edible metallic luster dust and cheap vodka.  She sprayed the cake, explaining that for complete coverage she would need to do that 5-6 TIMES.

I've seen it done by hand painting and even in that case, the decorator did 4 coats.  The quins absorb the first 2 coats, so it's only after the 3rd coat that they finally begin to look very metallic.

If you start with yellow star quins, or even the pastel star quins, you'll have faster, better results.  You can google those online.  Amazon carries them, too.  Search "gold edible food spray" on Amazon and you'll find the Wilton gold mist, as well as several others.

Yes, it works on bc - I've done it  

Thank you both so much! My buttercream crusts over really fast. Would it be better to use a non-crusting recipe, or can I just use piping gel to make sure the sprinkles attach securely?

I've only used SMBC, so I can't speak for crusting buttercream. 

I've done it on crusting buttercream.   Once when the BC was freshly applied and stuck the sprinkles on right away.  Another time I had to wait (due to the rest of the design) for the icing to crust over and a few hours later brushed on some thinned out piping gel and then added the sprinkles.   Then airbrushed the heck out of them.  Both worked equally well.

Oh, I'm so glad to know that it has worked well for you all. Thanks sooooo much!