Put butter into the mix bowl, add caster sugar. Whisk it until smooth. Add egg whisk to mix it well. Add sift cake flour and corn flour. Use the spatula to combine it.

Put the batter into the piping bags. Squeeze the batter in the baking mat on tray. Place chocolate chips to decorate. Chill it for 15 minutes. Preheat the oven at 160 degrees celsius, bake at 150 degrees celsius approx 20 minutes.