SEPARATE LEAVES OF WHICHEVER type of green you're using. If using escarole or curly endive, use just the pale inner leaves. (Outer leaves can be sauteed with garlic and chile-- delicious!) Gently cut or tear leaves into attractive pieces, wash and dry them and set aside. To cut pears, stand them upright and slice off a round from the side. Work your way around the pear, slicing it thinly into crescent-shaped pieces. If walnuts are really fresh, simply crack them and break them into quarters and eighths. If they aren't so fresh, toss them in a little walnut oil and toast them at 350F until lightly roasted, about 7 minutes. Prepare vinaigrette and use half of it to dress the leaves. Set them on salad plates. Dress pears with remaining vinaigrette and settle them into leaves. Scatter walnuts over salad along with cheese. Garnish with chervil and dust lightly with pepper.
VINAIGRETTE: In bowl, combine vinegar with salt, then whisk in oils. Adjust oil or vinegar to get the balance you like.