Mix marzipan with sugar, yolks, vanilla sugar and cocoa in a food processor or with a hand mixer. Pour the mixture into a piping bag and pipe small balls onto a prepared baking tray using a smooth nozzle. Bake in the preheated oven at 165 to 175 °C for 10 to 13 minutes, not too dark. For the cream, bring the whipped cream to the boil in a saucepan, dissolve the couverture in it, allow to cool slightly and stir in the rum. Just before the mixture begins to set, whisk it up, put it in a piping bag, spread each one on a cookie and put it together with another one. Dip halfway into dark chocolate icing. Sprinkle with cocoa and powdered sugar mixture or chocolate sprinkles just before icing.Chocolate icing:Melt chocolate glaze over a water bath or in the microwave over very mild heat. It should only be slightly warm. Dissolve coconut oil or butter in it and stir in.