Preheat oven to 350.
Line baking sheet with parchment paper.
Whisk together flour, cocoa, and salt.
Cream together butter and sugar until fluffy.
Add in egg and peppermint and mix until blended.
Slowly add flour mixture into creamed mixture.
Shape dough into a 1 1/2" - 2" round cylinder and wrap in wax or parchment paper.
Place in freezer for 1 hour to firm up.
You can cut down the length of an empty paper towel roll and wrap it around cylinder to help it stay more round.
Slice into 1/4" thick cookies.
Place on prepared sheet.
Bake 10 to 12 minutes.
Allow to cool.
Line baking sheet with parchment paper.
Melt chocolate by microwaving 45 seconds then stirring and repeating until chocolate is smooth and melted.
Dip cookies in the chocolate and lift out with a fork shaking off excess.
Place the cookies on prepared sheet and allow to set.