01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - Whisk together flour, baking soda, and salt in a medium bowl. Set aside.
03 - Beat softened butter, granulated sugar, and brown sugar until light and fluffy, about 2-3 minutes.
04 - Add eggs one at a time, mixing well after each. Stir in mint extract, vanilla extract, and green food coloring until evenly combined.
05 - Gradually add dry ingredients to wet mixture, mixing just until incorporated.
06 - Fold in chocolate chips and chopped dark chocolate if using.
07 - Drop dough onto prepared baking sheets using a tablespoon or cookie scoop, spacing about 2 inches apart.
08 - Bake for 9-11 minutes until edges are set and centers remain soft.
09 - Let cookies rest on baking sheet for 5 minutes before transferring to wire rack to cool completely.