Ingredients
1 pound dried Great Northern beans, rinsed
2 tablespoons extra-virgin olive oil, plus more for drizzling
3 leeks, white and light-green parts only, halved lengthwise, cut crosswise into 1/2-inch pieces, and well washed (4 cups)
5 cloves garlic, thinly sliced
1/2 teaspoon red-pepper flakes, plus more for serving
1 butternut squash, peeled, seeded, and cut into 1-inch pieces
3 sprigs sage
1 Parmesan rind, plus finely shredded Parmesan for serving
4 teaspoons fresh lemon juice
1 bunch spinach, trimmed and washed
Kosher salt and freshly ground pepper
Preparation
Place beans in a bowl; cover with 2 inches of water. Refrigerate, covered, overnight; drain and rinse. Cover with water in a saucepan. Bring to a boil; cook 10 minutes. Remove from heat; drain and rinse.
Place beans, oil, leeks, garlic, pepper flakes, squash, sage, and rind in a 5-to-6-quart slow cooker. Add 8 cups water. Cover and cook on low 6 hours. Remove and discard sage and rind; stir in lemon juice and spinach. Season with salt and pepper. Serve, drizzled with oil and topped with shredded cheese and pepper flakes.
