Preheat a 4-quart stockpot over medium heat and add the oil. Sauté the garlic in the oil for about 1 minute, being careful not to let it burn. Add the cauliflower, 3 cups of the broth (yes, only 3 of the cups!), thyme, salt, and pepper. Cover the pot and bring to a boil, stirring every now and again and boiling for about 10 minutes, or until the cauliflower is tender.
In a measuring cup, vigorously whisk together the remaining 1 cup broth and the arrowroot until dissolved. Lower the heat a bit so that the soup is at a low boil. Mix in the broth and cook uncovered for 5 more minutes, stirring often, until slightly thickened. Add the basil leaves and remove from the heat. Use an immersion blender, then use a blender or food processor to purée in batches, being careful to lift the lid once in a while to let the steam escape. Taste for seasoning.
Return the soup to the stove over medium heat and add the gnocchi; cover and let cook for 3 minutes or so. Add the greens and beans and cook until the greens are completely wilted and the beans are heated through, about 5 more minutes. Be careful as you stir not to crush the gnocchi or beans.
Serve garnished with extra basil and pine nuts, if you like.
