Chill a metal bowl and metal beater in the fridge for 15 minutes.

In a double boiler, melt the marshmallows and coffee together in the top over simmering water, stirring frequently and using a rubber spatula to scrap down the sides. Stir the banana and vanilla into marshmallow mix and set aside to cool.

Pour the cream into the chilled bowl and beat on high using the chilled beaters attached to an electric mixer until stiff peaks form. Gently fold the whipped cream into the marshmallow mix until well incorporated. Spoon the completed mixture into small dessert dishes and garnish with chocolate shavings. Let the dishes chill in the fridge for at least 30 minutes.