Bake cookies. Prepare macaron batter following recipe instructions. Combine Moss Green and Lemon Yellow icing colors to get green color shown. Tint batter green using color combination provided.

Prepare decorating bag with tip 12 and green batter. On parchment paper-covered jelly roll pan, pipe 1½ in. circles. Bake and cool following recipe instructions.

Helpful Hint: Create or use a macaron template to make evenly-shaped cookies.

Make icing. Prepare buttercream icing following recipe instructions. Prepare decorating bag with tip 7 and key lime icing. Fill and sandwich macarons.

Decorate macarons. Mix small amount White-White liquid color with tiny amount Lemon Yellow icing color. Using liner brush, paint lime slice on one side of macaron sandwich. Let dry, about 5 minutes.