Preheat oven to 160°C/320°F (you may add in a tray of water, about 2 cups, to increase the humidity).
*Pandan juice: Add 160 ml (⅔ cup) of water to 50 g (1.75 oz) pandan leaves, blend until fine, extract 150 ml (½ cup + 2 tbsps) of pandan juice.
Whisk together egg yolks, salt, sugar, pandan juice and corn oil until well blended. Sift together low protein flour and baking powder, then sift again into wet ingredients, mix until just combined (do not overmix, to avoid activating the gluten).
In another clean mixing bowl, whisk egg whites over low speed until frothy. Add in cream of tartar, continue whisking until soft peak. Add in sugar gradually, continue whisking until stiff peak (the peaks will point straight up and hold).
Add meringue into batter in 3 batches, mix gently using balloon whisk.
Fold gently using rubber spatula until well mixed.
Tap mixing bowl on countertop for a few times (to release large bubbles), then pour batter slowly into 22-cm loose bottom tube pan (do not grease), tap tube pan gently again on countertop for a few times.
Bake at 160°C/320°F for 45 minutes, then increase to 180°C/355°F and bake for another 10-15 minutes, or until fully cooked (the cake is done when the wooden stick inserted in the center of the cake comes out clean. (Reminder: The heat for different oven is different, the suggested time is only for reference, adjust the baking time base on your oven if necessary.)
Turn the pan upside down onto a wire rack (at least 6″ from countertop), set aside for 2 hours or until fully cooled.
Unmould the chiffon cake when it has fully cooled down.