With a food scissors, cut three pandan leaves (slightly wilted leaves) into small pieces, and add to a blender. Then add in one tablespoon of water at a time until the leaves blend into a fibrous, green mix.
Finally, pour through a strainer, and squeeze the fibers to release all the green water. Set bowl of pandan water aside.
Preheat oven to 350F (175C). Grease a 9-inch round cake pan with butter.
In two separate bowls, mix the dry ingredients (flour, baking powder, salt). Set aside.
In another two separate bowls, cream together the sugar and butter. Then mix in the remaining ingredients.
Add the dry ingredients into the wet ingredients, and combine well, but being careful not to overwork the batter.
Take turns adding the vanilla and pandan batter to the pan – using the ratio of two spoonfuls of vanilla batter to one spoonful of pandan batter.
Once the batter is all in the pan, it is important to lightly bang the bottom of the pan on the counter until all of the air bubbles in the batter are gone. Finally, use a knife to swirl patterns into the batter.
Bake for around 45 minutes – it’s done when a toothpick poked in the middle comes out clean. When done, set on a cooling rack for at least 15 minutes before serving.