Preheat your oven to 350°F (175°C) and prepare your baking sheet lined with parchment paper.

Cream softened butter and shortening together in a mixing bowl, then gradually mix in the granulated sugar until light and fluffy.

Add eggs and vanilla extract to the mixture, mixing until smooth.

In a separate bowl, whisk together flour, cocoa powder, baking soda, and salt before gradually adding to the wet ingredients.

Fold in hot chocolate mix and mini marshmallows into the cookie dough.

Scoop portions of dough onto the baking sheet, spacing them 2 inches apart.

Bake for 10-12 minutes until edges are firm but centers are still soft.

Allow cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack.