If using fresh beans, shell them, put them in a pot with enough cold, unsalted water to cover by about two inches, bring the water to a gentle simmer, cover the pot, and cook at a slow, steady pace until tender, about 45 minutes to one hour. Let them steep in their liquid until ready to use. If using dried beans, soak them overnight or for at least six hours, drain, then boil them in a fresh change of water untl tender. Let them steep in their liquid until ready to use.
Put the oil and chopped onion in a medium skillet, turn on the heat to medium, and cook the onions, stirring frequently until translucent but not coloured. Add the crumbled sausage and cook it, turning it over with a wooden spoon, until it becomes coloured a rich brown all over.
Retrieve the cooked beans from their pot, using a colander spoon or another slotted spoon, and put them in the skillet. Add one or two tablespoons of water from the bean pot, and mash about half the beans, pressing them against the bottom of the skillet with the wooden spoon.
Cook for about a minute, turning the contents of the pot over with the spoon from time to time. Pour the broth into a saucepan, bringing it to the boil and keeping it at a slow, sputtering simmer.
Place the heavy-bottomed saucepan where you'll be making the risotto on the burner nearest to the broth, empty the contents of the skillet into it, and turn the heat under the risotto pot to medium high. Stir, and when the beans and sausages are sizzling hot, add the rice. Stir quickly and thoroughly to coat the rice well.
Add one cup of simmering broth, and cook the rice, stirring it and periodically adding liquid. Finish cooking the rice, stirring always and adding broth when needed, until tender but firm to the bite, about 25 minutes.
Take the pot off the heat and do the mantecare step, swirling in the butter and Parmesan, turning the risotto over four or five times. Add the chopped parsley, salt and ground pepper to taste, stir once or twice more; transfer to a warm platter and serve at once.
What is mantecare? Mantecare is the final step of making risotto. The word is borrowed from the Spanish for butter, mantequilla. In Italian it means to work butter or cream into what you are cooking to give it a soft consistency. In making risotto you do this when the risotto is cooked but is still steaming in the pot. Add a tablespoon or so of butter and some freshly grated cheese, and swirl them in to combine. It is the final and best touch, giving the risotto its great consistency.