Lightly coat rice cooker inner pot with oil (line the bottom with parchment paper if it is NOT non-stick or the bottom tends to burn).
Combine cake flour and baking powder, then sift through a sieve.
Blend together milk and pandan leaves until very fine, measure out 70 ml of pandan milk.
Combine eggs and sugar in a mixing bowl, whisk until well mixed.
Combine 1000 ml of water with 400 ml of hot water in a large steel bowl to yield 45°C/113°F of warm water.
Dip mixing bowl in warm water bath, whisk egg mixture over medium speed until it starts to thicken, then reduce to low speed and whisk until the egg mixture is stiff (the ribbons formed by egg mixture will stay on surface for a while before dissolving slowly). (Reminder: Stop for a few times during this process to avoid overheating of the equipment.)
Combine corn oil, pandan milk and ½ of the flour in another mixing bowl, mix until smooth. Add in ⅓ of beaten eggs, mix until combined. Add in the remaining flour, mix until smooth.
Add the remaining beaten eggs in 2 batches, mix gently using hand whisk.
Fold gently using spatula until well mixed, then tap a few times on counter top to burst large bubbles.
Pour batter into rice cooker inner pot, tap again to burst large bubbles.
Cook in the rice cooker for 40 minutes, until wooden stick inserted in the centre comes out clean. (Reminder: I use “Quick Cook” setting, each cycle takes about 40 minutes. Different rice cooker functions differently, if your rice cooker switches to “Keep Warm” before the cake is cooked, you need to press the “Cook” for a few times, until the cake is fully cooked.)
Invert the rice cooker sponge cake onto a wire rack, set aside to cool for 15-20 minutes.