Melt the dark chocolate in a heatproof bowl over a saucepan of simmering water or in the microwave in short intervals. Let cool slightly.
In a large bowl, beat the cream cheese, sugar, vanilla, and salt until smooth and creamy.
Whip the heavy cream to soft peaks and fold it into the cream cheese mixture.
Fold in the melted chocolate until fully incorporated.
Spread the filling evenly over the chilled crust. Smooth the top with a spatula.