Soak the mung beans in water overnight, 24 hours if possible.
Rinse the soaked beans and put the beans in the pressure cooker.
Add 3 cups of water and salt to the pot.
Cover the pot and turn the temperature on 'Hi' for 10 minutes. If you prefer, you can follow the instructions provided by your pressure cooker for cooking the beans.
After 10 minutes, carefully remove the lid and add ½ cup of granulated sugar. Add more or less depending on taste. If there's a thin film on top, remove it using a spoon. Whenever I use the pressure cooker to make bean dessert, I always quick release right after it's done cooking. Otherwise, the beans will over cook.
Add ½ teaspoon of vanilla extract. Mix well & enjoy.
If you're going to add coconut topping, then pour a can of coconut milk into a pot. Add sugar and salt and stir to combine. Gently heat until mixture is warm. Give the coconut milk a taste then adjust the sweetness accordingly.