All you need is the right technique.
This style of cupcakes are perfect for special occasionslike parties, birthdays, and weddings.
Lay out a large piece of plastic wrap on a flat surface.
Spoon the first color of frosting onto the plastic wrap in a rectangular shape.
Do the same thing with the second frosting color.
Guide the sealed frosting, edge first, into a pastry bag, if you have one.
Cut the plastic wrap on the edge of your frosting “log” off.
Then refrigerate the whole thing for 15-20 minutes to help firm it up.
How to Make Swirled Cupcake Frosting| Food & Wine (YouTube)