Nothing could be tastier, or simpler, than this vibrant and refreshing lemon verbena sorbet on a hot summer's day. Wonderful! From 'The Herbfarm Cookbook'. Cook time is chill time. Note: For variation, you can make a lovely Scented Geranium Sorbet. Or, try an herbal addition. The pure flavor of lemon verbena blends well with other herbs. Herb Additions-- For a compound herb flavor, grind any of the following with the lemon verbena leaves and sugar: 1 cup sweet cicely leaves, 6 rose geranium leaves, 1/4 cup French or Mexican tarragon leaves, or 1/4 cup mint leaves.