tomato soup with goat cheese

1 bunch leeks, including greens
1 T unsalted butter
2 16-oz cans plum tomatoes, coarsely chopped
5 ½ c chicken or vegetable stock
3 T chopped fresh basil leaves
½ lb goat cheese
freshly ground black pepper

Cut off the roots and 4” of green ends of leeks and discard. Quarter them lengthwise and thinly slice. Soak them in several changes of water to get rid of sand. Chop well. Place a heavy stockpot over medium heat and when hot, add butter. When butter has melted, add leeks and cook until wilted, 10 to 15 minutes. Add tomatoes and their juice, stock, and basil, raise heat to high and bring to boil. Lower heat to low and cook, uncovered, 1 ½ hours. ..Turn off heat and gradually stir in goat cheese and pepper. Serve immediately, garnished with basil, or transfer to a container, cover, and refrigerate overnight. Serve hot or cold.

Note: if you reduce the stock to 3 cups, this makes a great sauce for shrimp and/or pasta.