Begin by preheating your oven to 350°F (175°C). Prepare your baking sheets by lining them with parchment paper to prevent sticking.
In a large mixing bowl, cream together the softened butter, brown sugar, and granulated sugar. Use a mixer on medium speed until the mixture becomes smooth, fluffy, and light in color—this should take about 2-3 minutes.
Once creamy, add in the egg, vanilla extract, and peppermint extract. Mix until all ingredients are thoroughly integrated. For an optional vibrant green color, add a few drops of green food coloring and stir until the dough achieves an even shade.
In a separate bowl, combine the all-purpose flour, baking soda, and salt. Whisk these dry ingredients together to ensure they are well mixed. Gradually incorporate this flour mixture into the wet ingredients, mixing gently with a spatula or wooden spoon until just combined—be careful not to overmix to ensure tender cookies.
Gently fold in the semi-sweet chocolate chips and mint chocolate chips, distributing them throughout the cookie dough so every bite is bursting with flavor.
Using a tablespoon or a cookie scoop, portion out rounded balls of dough onto the prepared baking sheets. Make sure to space them about 2 inches apart to allow room for spreading during baking.
Bake the cookies in the preheated oven for 10-12 minutes. Keep an eye on them; they should have lightly golden edges while the centers remain soft and chewy.
After baking, remove the cookies from the oven and let them cool on the baking sheet for about 5 minutes. This helps them set before transferring them to a wire rack to cool completely.
Notes
For a beautiful display, stack the cookies on a decorative plate, and sprinkle a few extra mint chocolate chips on top. Pair with a glass of cold milk for a classic and delightful treat perfect for sharing!