Soak the beans overnight.
Strain and wash.
Chop the Kombu seaweed.
Put the beans in a cooking pot, cover with water, add the seaweed and bring to boil.
Clean the foam, lower the flame to minimum and cook partially covered until soft for 1.5 hours.
Add more water to cover the beans, if needed.
If using a pressure cooker, cook for 45 minutes.
Remove the kernels off the corncobs.
In a skillet, fry in oil the whole spices, for 2 minutes, until browned.
Add the onion and fry until browned for about 7 minutes.
Add the corn, sweet potato and butternut squash and mix.
Add the cooked beans with the remaining cooking fluids and cook for another 25 minutes. Towards the end of cooking, add the salt.
Close the flame and add the chopped greens.