Remove the greens from a bunch of young turnips with greens. Trim and discard the stems from the greens. Wash and drain the greens and cut them into 1/2 inch strips. Trim the roots from the turnips (taste one to judge if the skins are tough), and slice thin. Warm 1.5 tbsp butter or olive oil in a heavy pot over medium heat and add 1/2 onion, sliced thin. Cook until soft, about 12 minutes. Add the sliced turnips with 1 bay leaf, 1 thyme sprigs, and salt. Cook for 5 minutes or so, stirring occasionally and cover with 3 cups chicken or vegetable broth. Bring to a boil, then turn down to a simmer and cook for 10 minutes. Add the turnip greens and cook for another 10 minutes or until the greens are tender. Taste for salt and add more if needed. Add a small piece of proscuitto or smoked bacon with the sliced turnips and herbs or garnish the soup with grated parmesan. You can also cook the soup in water instead of broth and stir in a couple of tablespoons of butter or olive oil at the end for richness.
adapted from "The Art of Simple Food" by Alice Waters 2007.