Edible gold luster dust is without flavor, and can be found at cake specialty shops and at most craft stores in the baking aisle. You can also easily find it online.
Luster dust shows up best against dark surfaces, so Hershey's™ Special Dark™ frosting is a perfect choice for this technique.
Use only soft-bristled artist's brushes. They help achieve an even gold coating without damaging the appearance of the piped frosting.
This technique can be used with silver luster dust for Silver Anniversary (25 years) treats.