Preparation Heat oil in heavy large pot over medium-high heat. Working in batches, sauté sausage until cooked through, breaking up with back of spoon, about 6 minutes per batch. Using slotted spoon, transfer sausage to bowl, leaving drippings in pot. Reduce heat to medium; add onion to pot and sauté until translucent, about 5 minutes. Add prosciutto and sauté 1 minute. Mix in garlic and crushed red pepper. Add escarole and sauté until wilted, about 2 minutes. Add wine and cook 2 minutes. Add beans, stock and sausage and simmer 10 minutes to blend flavors. Season to taste with salt and pepper. Transfer to large bowl. Top with grated Parmesan, if desired.