Cabbage Soup with Gruyere

1 tablespoon extra virgin olive oil
1 medium onion, chopped
1 russet potato, peeled and grated
3/4 pound cabbage (about 1/2 medium head), cored and shredded
Salt to taste
5 cups water, chicken stock or vegetable stock
1 Parmesan rind
Freshly ground pepper to taste
2 cups low-fat milk
1 cup grated Gruyere cheese

For garnish:
6 1/2-inch thick slices of French or country bread, toasted and cut into small squares
Minced fresh chives

Heat the oil over medium heat in a large, heavy soup pot. Add the onion and cook, stirring, until tender, about 5 minutes. Add the grated potato, the shredded cabbage and 1/2 teaspoon salt. Stir together for a minute, taking care that the potatoes don?t stick to the pot, and add the water or stock, the Parmesan rind and salt and pepper to taste. Bring to a simmer, cover and simmer over low heat for 30 minutes, until the vegetables are tender.

Add the milk to the soup. Stir to combine well and heat through without boiling. A handful at a time, stir the Gruy?re into the soup and continue to stir until the cheese has melted. Taste and adjust seasonings. Remove the Parmesan rind. Serve, garnishing each bowl with a handful or toasted croutons and a sprinkling of minced chives.