Grease sides and line base of a 22cm round cake tin with parchment paper. Bring water in a steamer to a boil over rapidly boiling water. Place eggs, sugar and ovalette in the bowl of an electric mixer fitted with a balloon whisk. Beat until light pale and fluffy.
Fold in half the sifted flour and gradually pour in milk. Add remaining flour and mix into a batter. Pour batter into prepared tin and place in the steamer. Sprinkle the top with combined almond nibs and black sesame seeds. Wipe off water from the steamer cover then steam over rapidly boiling water for 30-35 minutes. Remove cake and leave to cool.