Beat butter, powdered sugar and peppermint extract together, on medium speed, for 1-2 minutes until light and fluffy.
Reduce speed to low and mix in flour, cocoa powder, baking soda, and salt.
Take out the dough and roll it in a log. Wrap the dough in the saran wrap and put it in the freezer for 30-45 minutes. (Transfer into the fridge if you are not ready to bake yet).
Preheat the oven to 350 degrees. Line cookie sheet with parchment paper and grease lightly.
Cut the cookie dough into 1/4 inch rounds. Lay out the cookie dough onto the cookie sheet about 1 inch apart and bake for 10-12 minutes.
Cool cookies completely on a wire rack.
Melt milk chocolate and white chocolate melts, separately, in the microwave. Make sure to set the microwave at half power and heat for a 45 seconds- 1 minute. Stir until all smooth.
Dip cookies in chocolate and place them on parchment paper to set.
Sprinkle with peppermint crunch or sprinkles while chocolate is still wet or it will not stick.