In a separate bowl, combine milk, cooled coffee, powdered sugar, and melted chocolate.
Gently fold whipped cream into the coffee-chocolate mixture.
Divide the mousse into serving glasses or bowls and refrigerate for at least two hours, or until set.
Notes
Feel free to use decaffeinated coffee.TO STORE: Cover the mocha mousse in plastic wrap and store it in the refrigerator for up to 2 weeks. TO FREEZE: Transfer the mousse to a freezer-safe container and freeze for up to 6 months. Let it thaw overnight in the fridge.