Ingredients
Method
- In a large bowl, beat the butter, granulated sugar, and brown sugar together until fluffy and light, about 2–3 minutes.
- Add the egg and vanilla extract, then beat on high speed until combined, scraping the bowl as needed.
- In a separate bowl, whisk together the flour, cocoa powder, hot cocoa mix, baking soda, and salt.
- Gradually add the dry ingredients to the wet mixture and beat on low until combined. Mix in the milk. Dough will be thick and sticky.
- Cover dough tightly and chill for at least 2 hours and up to 3 days.
- Preheat oven to 350°F (177°C). Line baking sheets with parchment paper or silicone mats.
- Scoop and roll the chilled dough into balls (about 1 heaping tablespoon each) and arrange 2–3 inches apart on baking sheets.
- Bake for 10 minutes, remove from oven, and press a marshmallow half onto each cookie. Return to oven for 2 more minutes.
- Remove from oven and gently press the marshmallow to flatten slightly. Cool cookies on the baking sheet for 10 minutes, then transfer to a wire rack.
- Melt the chocolate in a microwave or double boiler. Spoon melted chocolate over each marshmallow-topped cookie and let set for 30–60 minutes at room temperature.
- Store cooled cookies tightly covered at room temperature for up to 1 week.
Notes
For a richer hot cocoa flavor, use a premium hot cocoa mix. To help the chocolate set faster, place cookies in the refrigerator for 10–15 minutes.