In a bowl, melt the butter with the chocolate in a bain-marie.
Beat the eggs with the sugar, salt and vanillin.
Add the chocolate to the mixture and add the sifted flour with the baking powder.
Lightly grease the mould and sprinkle it with flour.
Pour the dough into the pan (26 cm diameter) and bake in a static oven at 180 ° C for about 45 minutes.
Remove from the oven and test the toothpick, if it is dry the cake is perfectly baked. Leave to cool for 20 minutes.
Garnish and decorate as desired.