In a large bowl, beat butter and sugar together until fluffy. Stir in egg and vanilla.
In another large bowl, sift flour, baking powder, salt, baking soda, and nutmeg. Combine with first bowl alternating flour with sour cream. Place dough on a large sheet of plastic wrap, shape into a disk and wrap tightly; chill for 2 hours or overnight.
To make the cookies, preheat oven to 425˚F. Line two rimmed baking sheets with parchment paper.
Roll dough out on lightly floured surface to 1/4-inch thickness. Trace each child’s hands with a floured knife, making sure the child doesn’t press into the dough. Arrange cookies on lined baking sheet and refrigerate for 15 minutes.
Bake until the edges are lightly browned, about 6 to 8 minutes. Transfer cookies to a rack to cool completely before decorating.
In a small bowl combine sugar and milk, and mix until smooth.
Add corn syrup and almond extract, and beat until glossy.
Divide mixture into separate bowls; stir in a few drops of food coloring in each to make different desired colors. Paint icing onto cookies to make fingernails, rings, watches, etc., and let it set for 1 hour before serving.
Tip: Make sure you designate a separate brush for every color you use. Washing the brushes in between colors may dilute the icing. Add decorative sugars and sprinkles and edible balls (called dragees) for extra pizzazz.