Heat the olive oil in a large pot or Dutch oven over medium heat. Add the onion, carrot, celery, garlic, rosemary, salt, thyme, and several grinds of pepper. Cook for 8 minutes, stirring occasionally, or until softened. Add the beans and broth. Simmer for 20 minutes.

Transfer half the soup to a blender and blend until smooth. Stir the puree back into the pot and add the kale and lemon juice. Cook, stirring, until the kale is wilted, about 5 minutes. If the soup is too thick, stir in water, 1/2 cup at a time, until it reaches your desired consistency. Season to taste (I usually add another 1/4 teaspoon salt at this point) and serve with a drizzle of olive oil, croutons, and fresh parsley for garnish.