If it is fresh out of the refrigerator, allow eggnog to approach room temperature for 20 minutes or so.
Set the confectioners sugar (and cream of tartar if desired) in a bowl and add about half of the eggnog.
Mix slowly, adding more eggnog as you go until you achieve the desired consistency.
Store in a zip-top bag or icing bag.
After icing has been completely mixed, you may add more confectioners sugar to thicken a bit further. You may add small amounts of eggnog, about a teaspoon at a time, to thin it down for other purposes, such as color flow if you are coloring the icing.
Ice cooled cookies before the icing hardens.
Good to know that we both like Nancy Drew & Hardy Boys. my first crushes was Scott Baio and Shaun…