In a heatproof bowl, combine the dark chocolate and butter.

Place the bowl over a saucepan of simmering water (double boiler) or microwave in short intervals, stirring frequently, until melted and smooth.

Remove from heat.

Add the powdered sugar, half-and-half, and vanilla extract to the melted chocolate mixture.

Beat with an electric mixer until the frosting is smooth and has a spreadable consistency.