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

2. In a medium bowl, whisk together the flour, cocoa powder, baking soda, baking powder, salt, and espresso powder.

3. In a large mixing bowl, beat the butter, granulated sugar, and brown sugar until light and fluffy.

4. Add the eggs one at a time, mixing well after each addition, then stir in the vanilla extract.

5. Slowly mix in the melted dark chocolate until smooth and fully combined.

6. Gradually add the dry ingredients into the wet ingredients and mix until just combined. Fold in the chocolate chips.

7. Cover the dough and chill for 30–45 minutes.

8. Scoop about 2 tablespoons of dough, flatten slightly, place a chocolate truffle in the center, and wrap the dough around it completely.

9. Arrange cookie dough balls on the prepared baking sheet about 2 inches apart.

10. Bake for 9–11 minutes until the edges are set but the centers remain soft.

11. Remove from the oven and gently press half a marshmallow onto each cookie.

12. Return to the oven for 2 more minutes until the marshmallows soften and lightly toast.

13. Drizzle melted chocolate over the warm cookies and sprinkle with crushed candy canes if desired.

14. Allow the cookies to cool for 5 minutes before transferring to a cooling rack. Serve warm for the best gooey texture.