Take the apple peelings and combine them with 2-1/2 cups of water. Simmer over medium heat for approximately 20 minutes. Strain and set aside.
Combine the oil, fennel, leek, celery and green apples in a heavy bottomed saucepan. Sauté over medium heat for 20 minutes or until soft. Add white wine and reduce by half.
Pour in the apple stock you have set aside and continue reducing by half again. This strengthens the flavor of the soup. Add the heavy cream and simmer 10-15 minutes more. Soup will start to thicken slightly.
When the soup as cooled, ladle it into the blender and purée. Strain through a fine strainer. Season. Garnish each bowl with toasted almond slices.