Let the red bean soak for at least 8 hours.
. Remove the soaked water, and then pour 500 ml water into the pot. Boil the water with high heat , and then lower the heat to low. Simmer for 20 minutes. Turn off the heat and let the covered pot rest for 20 minutes.
Pour 500 ml water into the pot. Simmer for 15 minutes with medium-low heat.
Take 30 g red bean in a bowl, and remove its excess water. Add 1 tsp erythritol, and stir well.