In classic French cooking, a soubise sauce is made from onions and thickened with rice. This soup ages well–it is decidedly better the next day.
2 lbs turnips, (peeled) and trimmed, cut into large chunks
1 lb onions, peeled and cut into large chunks
6 c broth or water
2 t salt
6 T long-grain rice
pepper, to taste
chopped fresh tarragon or parsley leaves, for garnish
1. Put the turnips, onions, broth or water, and salt into a large heavy pot and bring to a boil. Add the rice, mix well, and cover. Lower heat and simmer for 50 minutes, or until vegetables are very soft.
2. In several batches, purée contents of pot in a food processor until very, very smooth. Return the purée to the pot. Or you can purée the soup with an immersion blender in the pot. Or you can forgo the purée altogether (in which case you should chop the vegetables more finely). Add pepper. Taste for seasoning. Reheat gently. Serve garnished with chopped herb.