Cook artichokes completely. Scrape leaves and finely chop bottoms. In a large saucepan (or pot), saut‚ onions and celery in butter. Stir in flour and make a roux.
Blend in chicken stock and lemon juice. Add bay leaf, salt, pepper, thyme, artichoke scrapings and bottoms Cover and simmer 20 minutes or until slightly thickened. Heat to boiling point.
Add egg yolks and cream. Garnish with lemon slices.
Optional: To make soup creamy, purée in blender.Servings: 6