Rinse the cannellini and put them in a large pot with 2 quarts water, the sage leaves and the garlic cloves. Bring the water to a boil, lower the heat, cover and simmer the beans gently for an hour, longer if needed, until they are tender. Add 2 teaspoons salt to the water.
While the beans are cooking, heat the olive oil in a nonstick pan and sauté the onions over high heat with a generous pinch of salt, until they begin to color, 6 to 7 minutes. Turn the heat to low, cover the pan and allow the onions to cook slowly, stirring occasionally, until they are soft and caramel-colored, at least another 20 minutes. Add the onions to the cooked beans.
Wash the kabocha squash, cut it in half and scrape out the seeds. Cut each half into thick slices and cut the slices into 1-inch dice. (Kabocha squash does not have to be peeled.) Rinse the kale, trim out the hard ribs and slice the kale or cut it into 2-inch pieces.
In a large soup pot, combine the diced squash, kale, leek, turnips, celery and carrots. Add 2½ cups water, the vegetable broth and the remaining ½ teaspoon salt. Bring the liquid to a boil, lower the heat and cook the vegetables for 12 minutes, until all are just tender.
Add the cooked beans with all their broth to the vegetables, as well as a pinch of crushed red chilies, the parsley and the oregano. Simmer everything together for 6 or 7 minutes to marry the flavors.
Add the lemon juice and some freshly ground black pepper and taste. Correct the seasoning with more salt, pepper and lemon juice as needed.
Drizzle olive oil over each serving, or garnish with a spoonful of basil or parsley pesto.
The Omnivore Way... For your meat eating friends, add slices of sautéed Italian sausage, either a traditional sausage or a lower-fat turkey sausage.