Preheat the oven to 155°C and line 2 baking trays with parchment paper.
Cream the butter and sugar until light and fluffy. Add in the eggs and vanilla essence , beat until well incorporated. Sift in the potatoes starch and plain flour, use a spatula to stir until well mixed.
In a piping bag fitted with nozzle 1M or 2D, pipe the batter into the baking sheets in the pattern of a big swirl. Bake in the oven for about 15-20 minutes.