Makes 2 cups
12 ounces semisweet chocolate chips
In a large bowl combine chocolate chips, cocoa powder and espresso powder. Set aside.
Heat cream in a small saucepan over medium heat until just simmering. Pour over chocolate chip mixture and let sit for 1 minutes, then whisk until mixture is smooth. Fold in marshmalllow fluff and mix until fully incorporated.
Serve immediately or let cool to room temperature and store covered in the fridge for up to 5 days. Reheat sauce before serving.