Preheat oven to 180℃

Beat the butter with icing sugar in the mixing bowl at high speed until white and fluffy.

Gradually pour in the milk and continue mix until combine.

Fold in Dr. Oetker Nona Cake Flour and Custard Flour into the mixture. Mix well.

Divide the batter to 3 portions. Add apple green colour to portion 1, cocoa powder to portion 2 and remain for portion 3.

Place each mixture into a piping bag, use a piping nozzle to press out the batter on the baking tray.

Bake at 180℃ for 20-30 minutes. Set aside.

Melt cooking chocolate in a bowl with microwave oven or by double-boiling. Decorate the cookies with melted cooking chocolate and sprinkles as desires.