Choose large Italian white beans, called Gigande, or substitute white kidneys or great northerns. The Gigande beans have a rich meaty flavor that is complimented by the zest of lemon and the nutty flavor of young arugula.
- Rinse the beans. In a large pot over high heat, combine the water, beans, bay leaf and rosemary sprig. Over high heat, bring to a boil. Reduce the heat to low and cover.
- Simmer, stirring from time to time, until the beans are tender to the bite and the liquid has been reduced by about half, about 2 hours. Add the pepper and taste, adding more salt if desired.
- Ladle into warm bowls, garnish with the arugula leaves and the lemon zest and serve immediately.