In large heavy saucepan, melt margarine over moderate heat; add onion, celery, carrots and chopped apples; cook, uncovered, until onion is soft, about 5 minutes.
Stir in chicken broth, sage, pepper and bay leaf. Raise heat to moderately high; bring to boil, about 5 minutes. Adjust heat so that mixture barely bubbles; cover and simmer 20 minutes or until carrots are tender. Remove and discard bay leaf and cool soup 5 minutes.
In electric blender or food processor, whirl soup in 3 batches, each 30 seconds. Return soup to saucepan, cover, set over moderate heat, and bring just to serving temperature, about 2 minutes. Ladle into bowls and float two apple slices on top of each serving.
A simple, delicious soup with favorite fall flavors of apples and sage packs the rich vitamins of carrots. It makes a tasty cold-weather appetizer.