Fill in cookies. Using parchment paper, make two parchment triangle bags. Thin down remaining teal and green icing to count of 10 following package instructions. Place in separate parchment bags; cut small tip in bags. Flow in teal icing on cookies with teal border and green icing on cookies with green border.
Using green icing, pipe staggering dots on teal cookies; immediately drag toothpick through dots to create pattern. Repeat with teal icing on green cookies.
Add gold star sprinkle to top of each cookie.
Let cookies dry 8 to 10 hours.