In a large soup pot over medium-high heat, combine ham or bacon pieces, lentils, and chicken broth; bring just to a boil. Reduce heat to low and simmer 1 to 1 1/2 hours or until lentils are soft. Remove 2 cups of cooked lentils and place into food processor or blender bowl; let cool 5 minutes (if you do not let cool slightly before processing, mixture will explode out of container and make a mess in your kitchen). After cooling, whirl until pureed. Stir pureed lentils into soup mixture. In a medium frying pan over medium-high heat, saut onion and carrots in butter or margarine until limp, but do not brown; add to lentils. Add thyme, nutmeg, salt, and white pepper; simmer another 30 minutes. Remove from heat and serve in soup bowls.