Step 1 mix sugar and eggs. Step 2 Add the flour and the salt. Step 3 break the chocolate into pieces and melt the chocolate with the butter in a double boiler. Step 4 Add the chocolate mixture and butter to the device. Step 5 pour the mixture into a mold silicone to be missed. Step 6 bake in a preheated oven at 180 ° C (gas mark 6) for about 25 minutes. Monitor the cooking, poking a knife point, it must be clean at the edge of the cake and slightly dirty at the centre. Step 7 allow to cool before unmould. Sprinkle with icing sugar. Serve with custard or a scoop of ice cream to vanilla.