In a medium bowl, whisk together flour, cocoa & salt
In a large bowl, beat sugar & butter with an electric mixer until well blended
Next, add eggs to butter/sugar mixture and beat until well blended.
Then, slowly add flour mixture to butter mixture. Stir with a spoon until well combined
Chill dough in the refrigerator for 1 hour
Preheat oven to 350 degrees
Line 2 cookie sheets with parchment paper
Using 1 tablespoon of dough at a time, roll into balls and place on cookie sheets 2 inches apart
Use palm of hand or the bottom of a glass dipped in water to flatten each ball
Bake in oven for 10 to 11 minutes
Transfer cookies on to a wire rack and allow to cool for 15 minutes
For Icing:
Place powdered sugar and butter in medium bowl and beat with electric mixture until well blended
Add peppermint extract and food coloring and beat on low speed until icing turns pink and is well blended
Spread 1 generous tablespoon of icing on bottom of one cookie and top with another cookie to make sandwiches
Roll edges of cookies in crushed candy canes so it sticks to the icing