Dandelions are a green with high food value which nature conveniently provides in abundance in early spring. Harvest leaves when they have barely opened and are only a few inches high; large leaves are bitter and should not be used.
Wash dandelion greens in warm water to remove dirt particles. Combine with cold water in soup kettle and simmer, covered, 10 minutes. Drain. Press through food mill and return to kettle. Add stock and basil and simmer 10 minutes. In separate bowl combine cream and egg yolk. Spoon ½ cup hot stock into cream mixture, blend with whisk, and return to kettle. Heat but do not boil. Garnish with croutons. (Also good cold.)