Bring to boil the coconut milk, pandan leaves, vanilla extract and sugar. Let the liquid cool for a while until it is not too hot too handle. Then, run it in a strainer. Set aside. In a separate large bowl, combine starch, flour, mungbean flour and salt. Gradually pour the warm strained coconut milk to the flour mixture. Mix well by using rubber spatula. Divide the mixture to 3 parts. Give green and red colorings to two parts of it and leave the last part white as it is. Put 2-4 serving spoon/ladle of the white mixture into a loaf pan already greased with vegetable oil and covered with plastic. Steam the first layer in a preheated steamer for 10 minutes. Use big fire to steam this Kue Lapis. Pour another 2-4 serving spoon/ladle of the red mixture on top of the white mixture. Make sure the measurement of the mixture for each layer is the same. Steam for 5 minutes. Pour another 2-4 serving spoon/ladle of the green mixture on top of the red mixture. Steam for 5 minutes. Repeat these last three steps alternately until the all mixture is finished. Once the last layer is poured to the pan, steam the whole Kue Lapis for 25 minutes before turning the stove off. Release, cut and serve the Kue Lapis once it is completely cold. To achieve nice and smooth Kue Lapis slices, cut the Kue Lapis by using a knife covered with plastic and greased with a little bit vegetable oil.