Preheat your oven to 350°F (175°C). Cream together 1 cup of unsalted, softened butter with ¾ cup of granulated sugar and ¾ cup of brown sugar until light and fluffy—about 2-3 minutes. Beat in 2 eggs and 1 teaspoon of vanilla extract until fully integrated.

In a separate bowl, whisk together 2 cups of all-purpose flour, ½ cup of Dutch-processed cocoa powder, 1 teaspoon of baking soda, and a pinch of salt. Gradually stir the dry mixture into the wet ingredients until just combined.

Gently fold in 1 cup of white chocolate chunks and 1 ½ cups of Lucky Charms marshmallows, mixing until evenly distributed. Reserve a handful of marshmallows for topping.

Cover the bowl with plastic wrap and chill the dough in the refrigerator for 30 minutes. Prepare baking sheets by lining them with parchment paper.

Scoop generous tablespoons of dough onto the prepared baking sheets, leaving space between each one. Press additional reserved marshmallows on top. Bake for about 10 minutes.

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