Preheat the oven to 325 degrees F (165 degrees C).

Combine egg whites and cream of tartar in the bowl of a stand mixer fitted with the whisk attachment. Beat egg whites until stiff peaks form.

Beat egg yolks and sugar in a separate bowl until sugar has dissolved.

Whisk water and pandan paste until smooth. Mix thoroughly into egg yolk mixture. Add corn oil. Fold in sifted flour.

Fold egg yolk mixture gently into beaten egg whites using a spatula. Pour into a chiffon cake mold.

Bake in the preheated oven until a toothpick inserted into the center comes out clean, 45 to 50 minutes. Invert cake mold onto a cooling rack immediately after removing it from the oven. Let cake cool upside down in the mold. Loosen cooled cake from the mold using a sharp knife.