Preheat the oven to 350 degrees. Line a baking sheet with parchment paper.
Whisk together the flour, cocoa powder, baking soda, and salt in a small bowl.
With a mixer or hand mixer, cream the butter, white sugar, and brown sugar together until creamy and smooth, about 1 minute. Add the egg, mint extract, and vanilla extract and beat until well combined.
Gradually add the flour mixture and beat until just combined. Stir in the chocolate chips.
Scoop the dough in rounded tablespoons and place on the prepared baking sheet about 2 inches apart.
Bake for 8-10 minutes, or until the cookies are set, but still soft in the center. Don't overbake. Remove from the oven and allow them to cool on the baking sheet for 5 minutes before moving them to a wire rack to cool completely.
Prepare the dipping chocolate by placing the dark chocolate wafers in a glass bowl with 1/2 teaspoon of coconut oil then put into the microwave for 30 seconds. Remove and stir then place back into the microwave for 20 seconds. Remove and stir then place back into the microwave for 10 seconds. Remove and stir until completely melted. If needed, continue cooking for 10-second increments. Be careful not to overcook the chocolate!
Dip half of each cookie into the melted chocolate and place them on a parchment-lined baking sheet. Immediately sprinkle the top of the melted chocolate with a few sprinkles if preferred. Allow them to dry completely. Store in an airtight container.