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 butter, granulated sugar, and brown sugar in a large bowl until light and fluffy, about 2-3 minutes.
04 - Beat in eggs one at a time. Add peppermint and vanilla extracts.
05 - Gradually mix in green food coloring until desired shade is achieved.
06 - Mix in dry ingredients on low speed until just combined.
07 - Fold in chocolate chips and chopped mint chocolate pieces if using.
08 - Drop rounded tablespoons of dough onto prepared baking sheets, spacing 2 inches apart.
09 - Bake for 9-11 minutes until edges are set but centers remain soft.
10 - Let cookies cool on baking sheet for 5 minutes, then transfer to wire rack to cool completely.