Line a baking sheet with parchment paper.
Sift together the flour, baking soda, baking powder, and salt.
In a separate bowl, whisk together the cooled melted butter, granulated sugar, brown sugar, vanilla extract, peppermint extract, and eggs.
Fold in the dry ingredients until well incorporated.
Add the chopped mint chocolate and chocolate chips to the dough and mix to combine.
Using a 2-inch cookie scoop, divide the dough into 24 scoops, adding to the lined baking sheet.
Chill the cookie scoops for at least 30 minutes or up to 3-4 days.
Preheat the oven to 350°F and line another large baking sheet with parchment paper.
Using your hands, shape the scoops of dough into round cookie balls, placing onto the baking sheet 1-2 inches apart from each other.
Bake at 350°F for 10-12 minutes until slightly golden and remove from the oven.
Top with flakey salt and allow to cool for 5-10 minutes. Serve warm or chilled.