Grease a loaf pan with butter and dust with flour.
Beat the cream with the salt for a minute, add the vanilla sugar and continue to beat until the cream is stiff. Place in the refrigerator until further use.
Mix the butter with the sugar until lightly frothy, gradually add the whole eggs. After each addition, stir until the mixture is uniform again. Then stir in the poppy seeds, nuts and rum.
Mix the flour with the baking powder and sieve on the mass. Carefully fold in with a silicone spatula. Fold in the whipped cream and pour the batter into the mold.
Bake at 175 ° C for about 45 minutes (stick test). Once the ingredients have cooled down, mix a glaze with them and cover the cake with it.
The cake stays fresh for a long time wrapped in foil and stored in a cool place.