Peel and dice the carrots and parsnips, then put in a big soup pot with the vegetable broth; add salt and pepper to taste.
Bring to boil over medium-high heat, then reduce heat to low and simmer gently for 15 to 20 minutes or until vegetables are very tender.
Cool.
Place mixture in blender and puree until smooth, using only enough broth to your liking.
Return the puree to a soup pot, stir in the lemon juice and herbs.
Heat over low heat and bring back up to temperature and serve hot.