Rinse the beans 5–6 times, until the water runs clear.
Cover the beans with cold water and soak overnight in the refrigerator.
The next day, drain, transfer the beans to a saucepan, cover with fresh water, and bring to a boil.
Simmer for 20–25 minutes, until the beans are tender.
Drain, then blend the beans in a food processor until completely smooth.
Notes
If the paste is too thin, let it cool—it will thicken as it rests. Still runny? Gently cook it in a pan for a few minutes nKeeps in the fridge for up to 4 daysn