Wash the orange in warm water to remove any wax or dirt.

Grate the orange zest and squeeze about 2 tablespoons of juice from the orange. Set aside.

In a large mixing bowl, combine the all-purpose flour, powdered sugar, vanilla sugar, a pinch of salt, and blanched almond flour. Mix well.

Add the grated orange zest and juice to the dry mixture, then add the cold butter pieces.

Quickly knead everything together until a smooth dough forms. Adjust with more flour if the dough is too soft.

Shape the dough into a log, wrap in plastic, and refrigerate for about 60 minutes.

Preheat your oven to 180°C (350°F) and line a baking tray with parchment paper.

Slice chilled dough into thin pieces and roll each slice into a ball.

Arrange the balls on the baking tray with space between them and gently press down.

Bake for about 10 minutes or until lightly golden. Allow to cool completely.

Chop white chocolate, melt in a double boiler over low heat, stirring until smooth.

Drizzle melted chocolate over cooled cookies and sprinkle with additional orange zest if desired.