Melt the butter and let it cool down lukewarm. Beat eggs, sugar, vanilla sugar, salt and orange peel for about 8 minutes until frothy. Mix flour, baking powder and almonds, fold into the mixture with a whisk. Fold in liquid butter. Chill for at least 15 minutes. Grease either a madeleine tray (for 12 pieces) or a brioche tray (for 6 pieces) and dust with flour.
Pour a third of the dough into the madeleine tray or half of the dough into the brioche tray. Bake the madeleines in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 10-12 minutes or the brioches at the same temperature for 15-20 minutes. Bake the remaining dough in the same way. Allow the cake to cool for 5 minutes, then turn out of the moulds. Let them cool down. Sprinkle with sugar or icing sugar