The soup begins to be prepared the day before, that is, the day before. At this stage, first let the beans soak overnight. Also the day before, blanch and scrape the pig's ear, leaving it very clean;

On the day the recipe is to be made, cook the beans in water as normal, along with the pig's ear, chorizo, black pudding, onions and garlic;

After a few minutes on the heat, add salt, coriander and pepper to taste;

If necessary, add more water. The most important thing is not to let it dry, as the broth is essential;

Now put the diced potatoes in the pan;

Let it boil until the potato is well cooked;

Then stir well as the soup cooks;

Before serving, transfer the soup to another container. In it, place a well-washed stone. This is the “secret” of this soup, as Portuguese culture maintains this tradition. But this is not mandatory!