Preheat oven (electric cooker: 175°C/circulating air: 150°C/gas: level 2). Place 1 paper baking tin in each of the recesses of a mini muffin tray (12 recesses).
Mix flour and baking powder. Separate the egg, chill the egg white. Mix egg yolk, sugar, vanilla sugar, butter and advocaat with the whisk of the mixer for about 4 minutes until white-creamy. Fold in the flour mixture briefly.
Pour the dough into the moulds and bake in a hot oven for about 15 minutes. Then let them cool down in the muffin tray for about 10 minutes. Lift out and let it cool down.
For the icing, sift icing sugar into a bowl. Add the egg white and stir to a thick icing until smooth. Divide the icing into 5 bowls. Colour 4 parts with a few drops of red, yellow, green and blue food colouring in pastel shades.
Darken 1 teaspoon of the pink icing with red food colouring.
Spread a teaspoonful of icing on each muffin. Leave to dry. Pour the rest of the icing into a disposable piping bag, cut off a small corner and decorate the muffins as desired.
Allow to dry.