In the bowl of a stand mixer (or a large mixing bowl with a hand mixer), beat together butter, sugars and vanilla for 1 minute. Add the eggs one at a time, mixing in between additions.

In a medium mixing bowl, whisk together flour, cornstarch, baking soda and salt.

Turn mixing speed to low and gradually add in the dry ingredients. Beat until just combined or until a soft dough forms. Fold in the mints, mint chips, and chocolate chunks with a spatula.

Cover and refrigerate for at least 1 hour.

Preheat oven to 350 degrees. Line baking sheets with parchment paper or silicone baking mats.

To bake the cookies, using a standard size cookie scoop (approximately 1.5 tbsp.) to form balls of dough. Place onto the prepared sheets, leaving at least 2 inches in between.

Place in the oven and bake for 10-12 minutes, rotating the sheet half way through the baking process. Remove from oven when cookies are golden brown in color around the edges. Let cookies cool on pan for 3-4 minutes, then transfer to a wire rack to cool completely.