Preheat your oven to 350°F (175°C) and line your baking sheets with parchment paper.
In a large mixing bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy.
Add in the vanilla extract and eggs, one at a time, mixing well after each addition.
In a separate bowl, whisk together the flour, baking soda, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
Fold in the semi-sweet chocolate chips, white chocolate chips, and crushed peppermint candies if using.
Using a cookie scoop or tablespoon, drop rounded balls of dough onto the prepared baking sheets about 2 inches apart.
Bake in the preheated oven for 9-11 minutes, or until edges are lightly golden. The centers may look slightly underbaked, which is perfect for a chewy texture.
Remove from the oven and let the cookies cool on the baking sheet for 2 minutes before transferring them to a cooling rack to cool completely.
For a festive touch, you can sprinkle extra crushed peppermint on top of the cookies before baking.
Store the cookies in an airtight container at room temperature for up to one week or freeze for longer storage.