Sift together flour, baking soda, baking powder in a bowl and set aside.
In a separate bowl, whisk together together the brown sugar, granulated sugar, sea salt, cocoa, and peppermint extract.
Add in the slightly melted butter to the sugar mixture and whisk until combined.
Next, add in the egg to the sugar-butter mixture and continue to whisk until the mixture is thick and smooth.
Add the flour to the wet mixture in two parts, and fold with a spatula until a dough forms.
Note: the cookie dough will appear dry at first, but will become the right consistency.
Chill the dough in the fridge for 10 minutes.
Preheat oven to 350F.
Line a baking sheet with parchment paper.
Use a small ice cream scoop to portion cookie dough and place mounds onto the prepared baking sheet, with 3" of space in between.
At this point, you can freeze the portioned cookie dough for baking at a later time.
Press chunks of chocolate peppermint bark into the cookie dough.
Bake the cookies at 350°F/177°C for 8-10 minutes, until the edges are slightly golden.
Note: For chewier cookies, leave the cookies slightly under baked.
Remove from oven and let the cookies cool on the baking sheet for 5 minutes before transferring to a wire rack to completely cool.