01 -
Preheat the oven to 175°C. Line baking sheets with parchment paper for non-stick baking.
02 -
In a stand mixer fitted with a paddle attachment, combine softened butter, granulated sugar, and brown sugar. Mix on low speed until combined, then increase to high and beat until light and fluffy.
03 -
Add the egg, milk, and vanilla extract to the creamed mixture. Mix until fully combined, scraping down the sides of the bowl once halfway through.
04 -
Add all-purpose flour, powdered hot cocoa mix, unsweetened cocoa powder, baking soda, and salt to the bowl. Mix until the dry ingredients are fully incorporated.
05 -
Gently add marshmallow bits and semi-sweet chocolate chips to the dough and stir until evenly distributed.
06 -
Cover the dough with plastic wrap and refrigerate for up to 36 hours to enhance flavor and control spread during baking.
07 -
Use a cookie scoop to drop uniform portions of dough onto the prepared baking sheets, spacing them adequately.
08 -
Bake one sheet at a time for 8 to 10 minutes, avoiding overbaking. Cookies should remain soft in the center upon removal.
09 -
Immediately after removal from the oven, press additional chocolate chips and marshmallow bits onto the warm cookies.
10 -
Allow cookies to cool completely on the baking sheet, permitting residual heat to finish baking.