Preheat oven to 180 degree Celsius.
Whip the yolks till pale yellow colour and add in sugar and stir in the oil
Whip the whites with sugar until stiff peak forms.
Fold the yolk mixture into the white mixture.
Bake for 25 mins at the middle rack of the oven.
Blend the durian meat till smooth.
Whisk the whipping cream till peaks stiff and add to the durian puree and chilled until for later use.
In a bain marie, heat up egg whites together with sugar until 70'c or till sugar is dissolved.
Let egg mixture cool down until room temperature or colder.
Pour mixture into a stand mixer and whisk till stiff peak, slowly add in the soften butter and let it whisk till combined. Add in durians flavouring. chilled until for later use.
To assemble the cake, slice the sponge into 3 equal layers.
Tap the sponge with some sugar syrup and layer with durian cream.
Add on the second layer of sponge and tap on some sugar syrup.
Layer with the final coat of durian cream.
Top with the final layer of sponge and tab on some sugar syrup.
Coat the whole cake with butter cream.