Melt the butter for the dough and let it cool down a little. Beat the egg white and salt with a hand mixer with a whisk on the highest setting until very stiff. Mix the sugar and vanilla sugar, gradually stir in. Mix the flour, baking powder and almonds, fold into the egg whites. Finally, carefully fold in the melted butter. Pour the dough into a saddle of venison mold.
Put the tin on the wire rack in the oven and bake for about 40 minutes.
Place the tin on a baking rack lined with baking paper, let cool down for 10 minutes, turn over and let cool.
Cut the chocolate into pieces, melt in a small saucepan in a double boiler, then sprinkle the cake with it.