Prepare buttercream as described above. Split into two equal portions and dye one half green and the other dark brown.
Fit two piping bags with frosting tips- one a grass tip and the other an open star. Spoon the green frosting into the bag with the grass tip, and the dark brown into the bag with the star.
Pipe on the design using the technique in the video above- short squeezes of the icing bag to create the grass on top of the cupcakes, then pipe on the next. Fill with 2-3 pieces of candy per cupcake.