I was craving mint and chocolate so I made some chocolate cupcakes and swirled chocolate and peppermint buttercream for the decoration. I'd heard about the technique a few years ago, but never tried it because it requires three piping bags, and I don't usually have that many on hand. I got an 8-pack of them for Christmas, so now was a great time to give them a go.
I did a Youtube search and found a quick video that shows the basics of how to swirl the icing.
I made a small batch of butter cream frosting and divided it into two bowls, so I could make one half chocolate and the other mint. For the chocolate I added cocoa powder and vanilla, and for the mint I added green food colouring and peppermint extract. I ended up with about a cup of each flavour. The best part about making two kinds of icing is that there are twice as many beaters/bowls/and spoons to lick. I highly recommend swirl cupcakes for this bonus alone.
I put each colour in a piping bag and tied an elastic around the top.
Then I cut off the tips of the piping bags, and placed them side by side in a third piping bag, with a coupler and a 1M tip.
Then I just decorated like normal and got a very fun result.
The mint and the chocolate were amazing in swirl form. One bite was minty chocolate, another bite was chocolatey mint. Really fantastic. I would definitely try the swirl method again and am already thinking about fun flavour/colour combos for next time.