2. In a large cooking pot, add washed azuki and water (extra). Bring it to a boil. Drain in a colander.
3. Add azuki beans, salt and pour 800ml water in the pot of slow cooker.
4. Cover the pot and cook on high for 2.5h, stirring occasionally. When the beans are soft, add sugar and mix well. Cover and cook for about another 1h on high, checking now and then to prevent burning.
5. Let cool the anko completely!
6. If you don't use it all at once, then you can store it in the freezer for up to 2 months. Split them to small balls and wrap each anko in plastic wrap. Store in a Ziploc Freezer bag.
If you don't use a slow cooker then :
1. Add azuki beans in saucepan or pot and cover with water (about 3cm above the beans). Bring to a boil and cook for 2 minutes, then drain and discard water.
2. Repeat once more as we need to cook them twice.
3. Add drained azuki beans in a clean saucepan or pot and cover with water about 3cm above azuki beans. Once it comes to a boil, reduce the heat to low and simmer for about 1 hour or more until the beans are soft, adding more water as needed. How do you know it's cooked? : try to squeeze one azuki bean, it should be crushed easily.
4. Add sugar and cook, stirring constantly until sugar melts. Keep simmering to evaporate the water. Turn the heat off when it reaches your preferred consistency.