Mix the butter with sugar, yolks and softened chocolate until creamy. Moisten the crumbs with the rum, sieve the flour with baking powder, beat the egg whites with salt to form firm snow.
Alternately fold in the breadcrumbs, hazelnuts, flour, milk and stiff snow.
Pour the mixture into a greased and floured saddle of venison dish and bake at 140-160 ° C (increasing heat) in the second rack for approx. 55 minutes.