Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper.

In a mixing bowl, combine the softened butter, granulated sugar, and brown sugar. Beat on medium speed for about 2-3 minutes, until light and fluffy.

Add in the eggs one at a time, mixing well after each addition. Then, mix in the vanilla extract and peppermint extract (if using) until fully incorporated.

In a separate bowl, whisk together the flour, cocoa powder, baking soda, and salt.

Slowly add the dry ingredients to the wet mixture, mixing until just combined.

Gently fold in the mini marshmallows with a spatula.

Using a cookie scoop or spoon, drop tablespoon-sized balls of dough onto the prepared baking sheet.

Bake for 10-12 minutes, or until the cookies are set around the edges but still soft in the center.

Let the cookies cool on the baking sheet for about 5 minutes before transferring them to a wire rack to cool completely.

Optionally, sprinkle crushed candy canes on top while they’re still warm.