Preheat oven to 160C.
Beat egg yolk and sugar until pale yellow, and sugar dissolved.
Add pandan paste, vanilla extract, salt, corn oil, and coconut milk into egg yolk mixture.
Mix until combined.
Sieve in black glutinous rice flour, and mix until no trace of flour found.
In a clean mixing bowl, add cream of tar tar and egg whites.
Beat egg whites until bubbly, and gradually add sugar while beating.
Beat until you get stiff peaks.
Fold in 1/3 of the meringue.
I like to use a balloon whisk, but you can use a spatula or your hands.
Fold in the rest of the meringue until combined.
Pour batter slowly into UNGREASED chiffon pan, this helps to minimize large air bubbles.
Drop pan on countertop a few times to get rid of big air bubbles.
Bake for 20 minutes at 160C, reduce oven temp to 150C and bake for another 20 minutes
Then reduce temp to 140C and bake for 10-20 minutes until cake springs back, and skewer comes out clean.
Invert to cool immediately, un-mould by hand when completely cooled.