In a dry heavy saucepan toast the cuminseed and the caraway seeds over moderate heat, stirring, for 2 to 3 minutes, or until they are very fragrant, and transfer them to a plate. In the pan cook the leek in the butter, stirring occasionally, for 5 minutes, or until it is very soft, stir in the broth and the potato, peeled and cut into-1/2-inch dice, and bring the liquid to a boil. Simmer the mixture for 10 minutes, or until the potato is tender, stir in the toasted seeds, the kielbasa, the cream, and salt and pepper to taste, and simmer the soup for 5 minutes. Just before serving, stir in the spinach. Serves 2. soup 67