Preheat oven to 350 degrees F.
Its best to line your baking sheet with parchment paper for this recipe.
In a large microwave safe bowl add the butter and mint, melt the butter. This should only take 15-25 seconds. Take a spoon and smash the mint into the butter to release the mint flavor. Cover and set aside for 8-10 minutes.
Using a medium bowl combine the flour, cocoa powder and baking soda; stir to combine and set aside.
Strain the butter from the mint and add the chunks of unsweetened chocolate. Microwave until melted, approximately 20-30 seconds; stir well. Repeat heating for 10 seconds at a time stirring between each heating until the chocolate is completely melted and smooth.
Add the brown sugar, granulated sugar, eggs and vanilla; whisk well to combine. Add flour mixture; stir to combine. Fold in semi sweet chocolate chips or white chocolate chips and walnuts.
Chill the dough in the refrigerator for 10 minutes before scooping by tablespoonful onto the parchment paper. Bake for 10-12 minutes or until set. Cool on pan for 2-3 minutes and transfer to a wire rack.