1. Gather all ingredients, including butter, sugar, eggs, vanilla, flour, hot cocoa mix, baking soda, salt, and chocolate chips.
2. Preheat the oven to 350°F (175°C).
3. In a large bowl, cream together butter and sugar until light and fluffy.
4. Add eggs and vanilla extract, mixing until well combined.
5. In a separate bowl, whisk together flour, hot cocoa mix, baking soda, and salt.
6. Gradually add the dry ingredients to the wet ingredients, mixing until a dough forms.
7. Fold in chocolate chips and marshmallow bits or small marshmallow pieces.
8. Chill the dough in the refrigerator for at least 30 minutes to enhance flavor and texture.
9. Line a baking sheet with parchment paper.
10. Scoop dough into small balls and place them on the prepared baking sheet, spacing them apart.
11. Bake for 9-11 minutes, or until the edges are slightly crispy and the centers appear set.
12. Remove from the oven and, if desired, press extra chocolate pieces or marshmallows on top while cookies are warm.
13. Allow cookies to cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.
14. Optionally, drizzle melted chocolate over the cookies for extra richness.
15. Store cookies in an airtight container to keep them soft for several days.
16. Reheat briefly in the microwave before serving for a warm, gooey texture.
17. Freeze extra cookies for later consumption if needed.
18. Enjoy your delicious Hot Chocolate Cookies with a warm drink!