Preheat the oven to 350°F (175°C). Line baking sheets with parchment paper.
In a large bowl, mix softened butter, granulated sugar, and brown sugar until creamy and smooth.
Add eggs one at a time, mixing well after each. Stir in vanilla extract.
In a separate bowl, whisk flour, baking soda, and salt.
Gradually add dry ingredients to wet ingredients, mixing just until combined. Overmixing can affect texture.
Fold in semi-sweet chocolate chips, white chocolate chips, and crushed peppermint candies using a spatula.
Scoop dough onto prepared baking sheets, spacing cookies about 2 inches apart.
Bake for 10–12 minutes until edges look set and centers stay soft.
Let cookies rest on the baking sheet for 5 minutes, then move to a cooling rack.