Pre-heat oven to 350F and spray a 9 inch cake pan with baking spray and line with parchment paper .
Place the flour, sugar, baking powder, baking soda and salt in a big bowl. Mix well.
In a large cup or bowl mix together the pandan water, olive oil, vanilla and vinegar. Mix well. Then pour it into the dry ingredients.
Mix well until you get a nice batter. It's okay to have some flour lumps. Better to not over mix. Pour that batter into a prepared 9 inch cake pan. Bake for 25-30 minutes at 350F.
Leave to cool in the pan for 5 minutes. Then transfer to a wire rack to fully cool.
Make the frosting while the cake is cooling down.
To make the icing place the white chocolate chips in a bowl and microwave for 1 minute to melt. Pour the heavy cream into a small sauce pan and bring up to a slight simmer. Add in the pandan flavoring. Mix well until you get the color and taste you want.
Pour that into the melted white chocolate and mix until everything is melted. Leave to chill in the refrigerator until you are ready to frost.
To serve place the Pandan Cake on a serving platter and pour the icing in the middle of the cake and push it out to the edges. Add more frosting to cover the whole cake. You can leave it plain or top with some fun sprinkles.
Slice and serve.