2. Put washed azuki to the pressure cooker and add enough water to cover the azuki. Bring it to a boil. Simmer for 1 to 2 minutes, then drain in a colander.
3. Transfer the boiled azuki to the pressure cooker again and add 640mL of water.
4. Cover and lock the pressure cooker, and turn the heat to high. When the pressure builds up, turn the gaz down to lowest heat and cook at high pressure for about 15 minutes. Turn off the heat and let the pressure come down naturally.
5. Remove the lid and add sugar and salt. Simmer for about 10 to 15 minutes until thickened, stiring occasionally. Turn off the heat.
If you don't use it all at once, you can store it in the freezer for up to 2 months. Split them to small balls and wrap each anko ball in plastic wrap. Store in a Ziploc Freezer bag.