- 1/4 cup minced onions
- 2 tablespoons butter
- 2 bunches watercress
- 1/4 teaspoon salt
- 2 tablespoons flour
- 4 cups chicken stock, boiling
- 2 egg yolks
- 1 cup heavy cream
- Salt and pepper to taste
In a heavy 2- to 3-quart saucepan, cook the onion in butter for 10 minutes, or until tender. Trim, wash, and dry the watercress, saving a few leaves for garnish. Add the leaves and tender stems to the onion. Sprinkle with salt. Cover and cook over medium-low heat for 5 to 10 minutes. Stir in the flour, cook for 5 minutes, add the boiling stock, and cook 5 minutes longer.
Puree the mixture in a food processor or blender or put through a food mill. Set aside, uncovered, until ready to serve.
To serve, reheat the soup to a simmer. Beat the egg yolks into the cream. Add the soup very slowly to the egg-cream mixture, whisking vigorously. Return the soup to the stove to heat but do not allow to simmer or the yolks will curdle. Season with salt and pepper. Immerse the reserved watercress leaves in boiling water for 30 seconds, shock in ice water, and use as garnish.