Barbara Kafka's Sorrel Soup

• 3 tablespoons butter
• 3 ounces sorrel leaves, cut crosswise into thin strips (2 cups)
• 5 cups chicken stock
• 5 egg yolks
• 1 1/2 cups heavy cream
• Kosher salt to taste

1. Melt the butter in a medium saucepan.
2. Add the sorrel, and cook over medium heat for 2 minutes, or until the sorrel has wilted.
3. Add the chicken stock.
4. Bring to a boil.
5. Lower the heat, and simmer, uncovered, for 20 minutes.
6. (The soup base can be made ahead to this point and refrigerated for as long as two days if the finished soup is to be served hot; if it is to be served cold, continue and then refrigerate.
7. The finished soup improves after sitting for a day.)
8. Beat the egg yolks and cream in a small bowl.
9. Slowly ladle in some of the hot soup base, whisking constantly, until a third of it has been added.
10. Whisking the remaining base in the saucepan, slowly pour in the egg-yolk mixture.
11. Slowly bring to a boil, whisking constantly, until it is thickened and coats the back of a spoon.
12. Remove from the heat.
13. If serving hot, add salt to taste and serve immediately.
14. If serving cold, refrigerate, whisking occasionally until it is fully chilled, to keep it smooth.
15. If it is too thick, thin with a little milk.
16. Add salt to taste before serving.

butter, sorrel leaves, chicken stock, egg yolks, heavy cream, kosher salt

Taken from cooking.nytimes.com/recipes/8980 (may not work)