Very delicious cake. I got this recipe from my sister, June (Cupcake Kasih).
250g caster sugar
1/2 cup milk
Beat butter and sugar until light and fluffy, add eggs one at a time. Mix till combine. Add vanilla. Spoon flour into the mixture (alternate with milk). Mix with wooden spoon till combine. Add chopped apple. Spoon the batter mixture into small paper cup and bake for 20 minutes at 170C.