Cream the cold unsalted butter, white sugar, and light brown sugar together until light and fluffy, about 2-3 minutes.
Add the room temperature egg and vanilla extract, mixing until fully incorporated.
In a separate bowl, whisk together the all-purpose flour, instant vanilla pudding mix, salt, and baking soda until well combined.
Gradually add the dry mixture to the wet ingredients, mixing on low speed until just combined.
Add the mint green gel food coloring and peppermint extract if using, then fold in the chocolate chips and chunks until evenly distributed.
Cover and refrigerate the dough for at least 30 minutes.
Preheat your oven to 350°F (175°C) and line your baking sheet with parchment paper.
Scoop rounded tablespoons of dough onto the prepared baking sheet, leaving space between each cookie. Bake for 10-12 minutes until edges are lightly golden.
Allow cookies to cool on the baking sheet for about 5 minutes, then transfer to a wire rack to cool completely.
