Melt the chocolate and butter together using a double boiler over low heat, stirring until smooth.
In a mixer, beat the eggs with the sugar until pale, fluffy and doubled in volume.
Slowly add the melted chocolate mixture to the eggs while gently mixing.
Add the flour and salt and fold carefully until combined.
Butter and flour the soufflé molds thoroughly, tapping out excess flour.
Fill the molds with the mixture.
Bake at 190°C for 10 minutes.
Remove from the oven and serve immediately with cream or vanilla ice cream.