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

2. In a large bowl, cream the butter, granulated sugar, and brown sugar until fluffy.

3. Add eggs one at a time, then mix in vanilla extract.

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

5. Gradually combine the dry ingredients with the wet mixture.

6. Fold in the chocolate chunks carefully.

7. Scoop dough onto the prepared baking sheet using heaping tablespoons.

8. Bake for 8–10 minutes or until the edges are set.

9. Remove from oven and press a marshmallow half into each cookie.

10. Return to oven for 2–3 more minutes until marshmallows puff.

11. Let cookies cool on the sheet for 5 minutes, then transfer to a wire rack.

12. Serve warm for the ultimate hot cocoa cookie experience.