- 2 cups dried Great Northern beans (about 13 ounces)
- 8 cups water
- 1 onion, cut into 8 wedges
- 3 bay leaves
- 1/2 cup extra-virgin olive oil
- 12 1/4-inch-thick lemon slices
- 8 ounces fresh shiitake mushrooms, stemmed, caps sliced
- 3 tablespoons chopped fresh parsley
- 3 tablespoons chopped fresh thyme or 1 tablespoon dried
- 3 tablespoons chopped chives or green onions
- 3 tablespoons fresh lemon juice
- 2 cups chopped seeded tomatoes
- 1/2 cup grated Parmesan cheese (about 1 1/2 ounces)
- Place beans in large pot. Add enough cold water to cover beans by 3 inches; let stand overnight. Drain.
- Return beans to same pot. Add 8 cups water; onion and bay leaves. Bring to boil. Reduce heat; cover and simmer until beans are tender, stirring occasionally, about 1 hour. Reserve 1 cup cooking liquid. Drain beans; transfer to baking pan. Discard onion and bay leaves.
- Meanwhile, combine oil and lemon slices in heavy medium saucepan. Simmer over low heat until lemon slices are translucent, about 5 minutes. Let cool uncovered 30 minutes. Strain lemon oil into bowl. Transfer 4 lemon slices to plate; cut in half and reserve (discard remaining lemon slices). (Beans, cooking liquid, lemon oil and lemons can be prepared 1 day ahead. Chill separately.)
- Heat 4 tablespoons lemon oil in heavy large pot over medium-high heat. Add mushrooms and sauté until brown and tender, about 5 minutes. Add beans, 1 cup reserved cooking liquid, remaining lemon oil, herbs and lemon juice to mushrooms. Simmer over medium heat 5 minutes to blend flavors. Cool completely.
- Stir chopped tomatoes and grated Parmesan cheese into bean mixture season to taste with salt and pepper. Spoon bean mixture onto platter. Garnish with halved lemon slices.