Add flour mixture a third at a time, making sure its well mixed before adding the next third.
Preheat Oven to 350 F (176 C)and line two cookie sheets with parchment paper. (I had to bake two sets of cookie sheets for a total of 28 cookies.)
Roll cookie dough into small balls with your hands. Place each cookie dough ball into a bowl with the granulated sugar, roll around for a light coating.
Next, place dough balls 2 inches apart on cookie sheet.
Use a rounded 'tsp' measuring spoon to press a perfect 'thumbprint' into your cookie dough. (only press halfway down)
Warm the eggnog and combine with white chocolate chips in a microwave safe bowl. Heat for 1.5 minutes in microwave, stirring every 30 seconds until melted and smooth.(You can also use a double boiler if preferred.)
Store cookies in an air tight container at room temperature or in the fridge.