1. Preheat oven to 350°F (175°C) and line baking sheets with parchment paper.

2. Cream softened butter with granulated and brown sugars until light and fluffy, about 2–3 minutes.

3. Add eggs one at a time, mixing well after each, then stir in vanilla extract until smooth.

4. In a separate bowl, whisk together flour, cocoa powder, hot chocolate mix, baking soda, and salt.

5. Gradually add dry ingredients to wet mixture, mixing on low speed until just combined.

6. Fold in chocolate chips using a spatula.

7. Scoop dough into heaping tablespoons and flatten each piece in your palm.

8. Place one or two mini marshmallows in the center of each dough piece and wrap dough around to seal.

9. Chill filled dough balls on a parchment-lined sheet for at least 30 minutes.

10. Bake chilled cookies for 9–11 minutes until tops lose shine and small cracks appear.

11. Let cookies rest on the baking sheet for 5 minutes, then transfer to a cooling rack to finish cooling.