Melt the margarine in a large saucepan over medium heat. Cook and stir the apples and pears in the melted margarine for about 5 minutes.
Add the vegetable broth, sage, pepper, and bay leaf to the pan; bring to a boil. Reduce heat to low.
Place a cover on the saucepan and allow the mixture to simmer until hot and the apples and pears are tender, about 20 minutes.
Remove from heat and allow to cool for 5 minutes.
Pour about 1/3 of the soup into a blender, filling the pitcher no more than halfway full. Hold the lid of the blender in place with a towel and carefully start the blender, using a few quick pulses to get the soup moving before leaving it on to puree. Puree in batches until smooth; pour into a clean pot. Alternately, you can use a stick blender and puree the soup right in the saucepan. Return the pureed soup to the saucepan and warm over medium heat until completely reheated.