Preheat over to 300°F
To make the pandan extract, blend the pandan leaves with 2 tbsp of water and 2 tbsp of coconut milk. Sieve the blended pandan leaves to obtain the extract. Set aside.
Beat egg yolks until the color lightens. Add sugar. Continue beating until the mixture is even and creamy.
Sift the cake flour and baking soda until it's fine - set aside.
Add oil, the rest of the coconut milk, and pandan leaves extract. Mix well. Add sifted baking powder and cake flour into the mixture.
To prepare meringue, add sugar to egg whites a little at a time. Beat at high speed until it is foamy. Once it begins to foam, add vinegar.
Continue beating the egg whites at medium speed. Add salt too. Beat the egg whites mixture until stiff. Do not overbeat.
Add the meringue into the batter in batches. Fold in till batter and meringue are mixed thoroughly.
Bake at 300°F for 1 hour or until golden brown. Once brought out of the oven, place it upside down on a cooling rack and leave until it cools to room temperature.
Slowly pour the batter into a non-stick mould (7in - 8in) while tilting the mixing bowl to eliminate any air bubbles. You can also use a rubber spatula to remove any last air bubbles.