1) Wash the mung beans.
2) Put the beans in a pan and cover with water.
3) Cover the pan with a lid and let the beans stand at room temperature for 15 hours, or overnight.
4) The next day, drain the mung beans and rinse them well.
5) Let the beans dry for 20 minutes.
6) Place the mung beans in steaming plate.
7) Add the milk and coconut milk and stir well.
8) In a pan, place a steaming rack and add just enough water for steaming.
9) Place the steaming plate on the rack, cover the pan and let the water boil on high.
10) Once the water is boiling, reduce the heat to medium. Cook till all the water has evaporated (takes about 17 minutes).
11) Once the beans are done, move them to a plate and let them cool for 30 minutes.
12) Mash the now cool mung beans, and then add the sugar. Mix well and follow with the salt and butter. Stir all the ingredients together.
13) Put the paste in a pan over medium high heat and fry for about 5 minutes, stirring constantly.
14) After 5 minutes, turn the heat to low and cook for another 10 minutes.
15) Take the paste off the heat and add the vanilla essence. Stir well.