Sift the powdered sugar in your mixing bowl and set aside.
4¼ cups Powdered sugar
In a measuring cup, whisk the water, meringue powder, vanilla extract, and cream of Tartar, if using.
6 tablespoon Water, 2½ tablespoon Meringue powder, ½ teaspoon Cream of Tartar, 1 teaspoon Vanilla extract
Using the paddle attachment, add the wet ingredients to the powdered sugar. Once the ingredients are combined, turn the mixer on high for about a minute.
Adjust the consistency to use for Bordering. Icing these cookies requires two kinds of consistency. The stiff icing is used to make the border around the cookie's edges, and the runner consistency is used for the flooding to cover the cookie's surface.
Do the ribbon test to see if the icing is ready. Dip a spoon into the icing and lift it. If the icing drops into the bowl and the ribbon takes 3 to 4 minutes to disappear, the icing is ready to use for the Bordering. If the ribbon disappears into the bowl immediately, the icing is ready for Flooding.
Let the icing set for an hour or so, depending on the icing consistency and your kitchen temperature.
For the ghost's eyes, melt some chocolate in the microwave or over the double boiler. Place a dot of the melted chocolate on the cookie for the eyes and the mouth, then use the tip of a small spoon to drag the chocolate down to create that ghost look!
1 tablespoon Chocolate chips