Beat egg whites in clean, large bowl with mixer at high speed until foamy. Gradually add sugar and clear vanilla extract. Beat at high speed until thickened. If you desire a thicker icing, slowly add more confectioner's sugar until you reached your desired consistency.
For "Earth" cookies you will need: blue paste food coloring, green paste food coloring 3 Ziploc baggies or icing bags
Divide the icing into: 1/2 to color blue, 1/4 to color green and 1/4 white. Fill in green for land, blue for water and use the white to outline the land.