Chemistry: Mole Day Cookies

Courtesy of Deborah Gross

This recipe is meant to be enjoyed on Mole Day, celebrated by chemists and their allies annually on October 23, with festivities concentrated at 6:02 am (one mole is 6.02×1023 atoms or molecules, hence the celebration on 10/23 at 6:02 am).


  • 1 – 2 packages of ¼” white candy eyes (such as these from Amazon) – you will need ~160 eyes
  • 2 bags Hershey’s chocolate kisses (plain), foil and labels removed – you will need ~80 kisses
  • 1 1/4 cups (2.5 sticks, 282.5 g) butter, softened
  • 2 C (396 g) white sugar, plus 1/3 cup (66 g) for rolling cookies
  • 2 eggs
  • 2 tsp (10 mL) Vanilla extract
  • 2 1/2 cups (355 g) AP flour
  • 3/4 cups (64 g) unsweetened cocoa powder
  • 1 tsp baking soda
  • 1/2 tsp salt


  • This recipe makes ~80 cookies that are 14 g each (before baking). 
  • Preheat oven to 350 F (175 C).
  • Remove wrappers from chocolate kisses before starting the recipe.
  • In a large bowl, cream butter and 2 cups (396 g) sugar until fluffy, by hand or with a mixer.
  • Add eggs and vanilla extract and mix well to incorporate.
  • Sift together flour, cocoa, baking soda, and salt, and add in batches to the butter mixture, mixing after each addition.
  • Once the dough is uniform, roll dough into balls of ~15 g each (about 1” diameter) and roll each ball in the 1/3 cup (66g) sugar to coat the outside.
  • Place balls on an ungreased cookie sheet, ideally lined with a silicone mat or parchment paper.  Space them a few inches apart.
  • Bake for 10 – 11 minutes, or until cookies are still soft but starting to develop a crust, and the centers are not too soft.
  • Remove from the oven, place on a cooling rack and immediately (while cookies are still warm) place a chocolate kiss on its side in the middle of the cookie, to make the mole’s nose.  Press firmly.  It should start to melt a little bit.  If it melts significantly, wait a few minutes for the cookies to cool somewhat, but it is important that it melts somewhat.  Place two candy eyes on either side of the wide base of the chocolate, sticking them into the slightly melted chocolate.
  • Let cookies cool completely and enjoy!

This recipe is modified from “Jeanne’s Chocolate Kiss Cookies” at by Deborah Gross.