Chop white couverture, melt over a warm water bath. Soak gelatine in cold water. Whip cream until stiff. Beat 2 eggs with the whisk of the hand mixer. Squeeze the gelatine and dissolve.
Mix the liquid chocolate with the whipped eggs, stir in the gelatine and carefully fold in about half of the cream. Chill for about 2 hours.
Chop dark chocolate and melt it over a warm water bath. Beat 2 eggs with the whisk of the hand mixer. Mix the liquid chocolate with the beaten eggs. Carefully fold in the remaining cream.
Chill for about 1 hour.
Cream butter, sugar and vanilla sugar with the whisk of the hand mixer. Stir in 2 eggs one after the other. Mix flour, baking powder and cocoa and stir in briefly with milk and rum. Preheat waffle iron, spread with oil and bake about 4 waffles one after the other.
Let waffles cool on a cake rack.
Pour the light and dark mousse into a piping bag with a medium perforated spout. Spray alternately light and dark tuffs onto the waffles. Place the wafers on top of each other and dust the edges with icing sugar if necessary.