Heat the oil in a large saucepan over medium heat.
Cook the sausage, turning occasionally, until browned and cooked through, about 10 minutes.
Transfer to a cutting board and let rest at least 5 minutes before slicing.
Add onions to the pan and cook over medium heat, stirring occasionally, until soft, about 6 minutes. Add the garlic and cook, stirring, 1 minute more.
Add the wine and broth and bring to a boil. Add the beans, escarole, salt, and pepper and cook, stirring occasionally, until the escarole wilts, 3 minutes.
Spoon into bowls and top with the Parmesan. Serve with the sausage and bread, if desired.