In a pot, combine the rinsed dried black beans, 100g white onion, 15g garlic cloves, and enough water to cover by about 5 cm. Bring to a boil, then reduce heat and simmer until the dried black beans are tender (2-3 hours).
3
Drain the cooked black beans, reserving some cooking liquid. Discard the cooked white onion and garlic cloves.
