250 g food-quality dark chocolate (70% cocoa), chopped
150 g mini marshmallows
275 ml double cream
50 g butter, softened
60 ml hot water
1 tsp. vanilla extract
Toss the chocolate chunks and marshmallows into a heavy-bottomed saucepan.
Dot with water and heat over slowest flame until the ingredients melt while making a point to stir frequently.
Turn off the heat and set aside.
Beat the cream with a splash of vanilla extract until it thickens and pour in the melted mixture.
Fold them together into a smooth, gooey blend and divide it among 6 small ramekins.
Refrigerate until the mousse sets.