Artichoke Soup

4 button mushrooms, sliced
1 small leek, finely chopped
2 teaspoons unsalted butter
2 (10 ounce) cans chicken broth
1 (19 ounce) can artichoke hearts, drained
1 tablespoon lemon juice
1/2 teaspoon green peppercorns
1 tablespoon sherry wine (optional)

Clean and slice the mushrooms. Trim the leek, discarding the roots and dark green portions. Chop it fairly finely, and rinse and drain well.
Melt the butter in a large saucepan over medium-high heat, and saute the leeks and mushrooms until soft and lightly browned.
Add the chicken stock, and reduce to a simmer.
Drain the artichokes, and chop them finely. Add them to the soup.
Season with the lightly crushed peppercorns, lemon juice and sherry. Check seasoning, and adjust with a little salt if needed.
Simmer for 5 minutes further, then serve.