Top Secret Chocolate Cookies

In a large bowl, add the butter and sugar and cream together with a hand mixer. Add the eggs and vanilla extract to the creamed mixture and mix until combined. In a medium bowl, mix the cocoa powder, flour, baking soda, and salt. Slowly add the dry ingredients and continue mixing until incorporated. Roll the dough into 2 logs that are about 2-inches high and 1-foot long. Wrap them in waxed paper and place in the refrigerator for 2 hours. Preheat oven to 350 °F. Once thoroughly chilled, slice the cookies into 1/2-inch thick rounds and cover with sanding sugar. Place on a parchment paper lined cookie sheet and bake for 10 minutes. Remove to a wire rack to cool.