The night before, soak the fabes beans in cold water. In the morning, drain the water.
Place the drained beans in a large pot. Add the pork shoulder, pancetta, chorizo, and morcilla. Cover everything with cold water.
Bring the pot to a boil over high heat, then reduce the heat to a low simmer. Skim off any foam that forms on the surface. Cook for about 2 hours.
In a small bowl, mix a ladle of broth with the saffron threads and sweet paprika. Stir well and add this mixture back to the pot. Stir gently once.
Continue to simmer for another 30 minutes to 1 hour, or until the beans are very tender and the broth has thickened. The beans should be creamy but not mushy. Add salt to taste.
When the fabada is ready, remove the meats. Slice them into pieces and return them to the pot.