First, apply a thin border of buttercream around the outside of your products. Pipe the buttercream quickly enough that it does not dry. It should be just a simple outline around the border of the cake or cupcake.
Next, brush the thin lines of buttercream using a small brush and keep the brush wet so it does not cling to the buttercream. In addition, clean the brush thoroughly every few brush strokes, so the pattern does not become messy. Once you have completed the border, the brush embroidery lends an interesting and original texture to your product.