Add all Icing ingredients except food coloring to a medium bowl and mix with an electric mixer. Mix for 5-8 minutes until the peaks are stiff. Before this, it might be a bit like a glaze.
Add about two thirds of icing into a bowl. Add the green food coloring until you think it is a good green color (add a little at a time).
Put the white and green icing into two piping bags. if you don’t have a piping bag, use a zip top bag and cut a small hole in the corner (which is what I used).
Flip over the cookies (icing the bottom). Pipe icing to cover them with the green icing and shake the cookie until the icing is flat. Work in groups of 3 at a time.
Add one dot of white icing in the middle and a circle around the edge of the cookie.
On the outside circle, take a toothpick and run the toothpick into the white dot in the middle. This will resemble a cut lime.
Allow cookies to set for 1-2 hours to harden and firm up. You can also serve them soft if you prefer.