serves: 6 servings
You don't have to use cannellini beans. Kidney beans, chickpeas, or just about any beans you like can go into this salad. Whichever beans you use, cut the onion thin at the last minute so it stays crunchy.
¾ cup braised Cannellini beans (see below)
½ pound dried cannellini or other small white beans, (about 1 1/4 cups), such as baby limas
4 sprigs fresh rosemary
2 tablespoons extra-virgin olive oil
freshly ground black pepper
1½ tablespoons red-wine vinegar, or to tatse
For the Brasied Cannellini: Pour the beans into a deep bowl and pour in enough cold water to cover them by 4 inches. Let soak in a cool place or the refrigerator at least 8 hours overnight.
Drain the beans and transfer them to a 2-quart saucepan. Pour in enough water to cover by two fingers and drop in two of the rosemary sprigs. Bring the water to a boil, then lower the heat so the water is at a bare simmer. Cook until the beans are tender but not mushy, with just enough liquid to cover them, 30 to 40 minutes. (If necessary, add more water a tablespoon at a time to keep the beans covered as they simmer.)
Remove the beans from the heat and gently stir in the oil, salt to taste, and the remaining 2 rosemary sprigs. Let stand to cool and absorb the cooking liquid. The end result should be tender beans with a creamy consistency in just enough liquid to coat them. Taste the beans occasionally as they cool and stir in more salt if necessary.
For the Arugula and White-Bean Salad: Fish the right amount of beans out of the cooking liquid and let them cool completely on a baking pan.
Meanwhile, pluck off the protruding stem ends of the arugula and discard any wilted or yellow leaves. Wash the arugula in a large bowl or sinkful of water to remove all sand and grit. Dry the arugula well, preferably in a salad spinner, and transfer it to a large mixing bowl. Scatter the cooled beans and the onion over the greens, and season everything with salt and pepper. Pour enough of the olive oil over the salad to coat the leaves lightly, toss to coat, then repeat with the vinegar. Check the seasoning, adding more salt, pepper, oil, or vinegar as you like. Serve immediately.