Whisk together cocoa powder, flour, and salt.
Beat 1 cup of sugar and 1 cup of butter together with a mixer.
Add egg and vanilla, beat in. Slowly add cocoa powder/flour mixture.
Roll dough into balls, about a tablespoon full. Roll ball in sugar then place on ungreased baking sheet. If dough is too sticky, cover with plastic wrap and leave in refrigerator at least an hour.
Bake in 350 degree oven for 5 min. After 5 min use melon baller to make an indentation in the center. Bake for 2 more minutes.
Add candy of your choice. I used candy cane Hershey kisses, Andes mints, and some mint chocolate chips. Bake for about 2 more minutes, don't burn candy!
Let cool on a cooling rack and enjoy!