Put 2 cups of dry white beans - whatever you have, and put in a large bowl and cover 2 or 3 inches of water. Soak overnight if you have time, but I find 8 hours is usually enough, and a max of 24 hours.
Rinse beans and sift through them to make sure there are no rocks or debris, and put into a large pan. Cover with chicken stock (approximately 750ml -1 liter) and bring to a light boil.
Slice the chorizo into 1/4 inch slabs and in a separate pan cook the chorizo, until. they start to brown, and have released a lot of their oil, drain with paper towel and set aside.
Add onion, garlic, bay leaves, bone, chorizo, and ribs to the beans and stock
Let simmer for 90 minutes to 120 minutes. Taste the beans at 90 minutes to see if they have softened, and if not keep cooking and retry every 15 minutes.
Taste for salt at the end, the Jamón bone imparts a lot of salt, I needed to add about 3/4 tsp at the end. It also depends on how salty your stock is. But be careful. Better to have too little than to much, as you can always salt it more when you serve it.
Optional step: When you think the soup is 15 minutes from done add 2 large chopped carrots, and 1 celery stick chopped, other options cook include spinach, kale, or potatoes
When the beans are soft, and you are happy with the flavor, turn off the heat and take out the bone, ribs, bay leaves and onion.
Let the bone and ribs cool, then take the meat from them discarding the fat, or save it - just don't put the fat back into the soup. I like to shred the meat.
Stir the meat back into the soup.
When ready to serve, drizzle some EVOO on top. I like a teaspoon, Spaniards usually put on a tablespoon. I like to garnish with just a little paprika for color.
I like to serve it with crusty bread