Melt butter in large saucepan over medium-low heat. Add onion and cook 8 minutes. Add flour, whisking until smooth. Cook 3 minutes. Add 1 cup of hot chicken broth, whisking vigorously to blend. Whisk in 5 more cups broth. Bring to a simmer, stirring.

Whisk egg yolks and cream together in a large bowl. Ladle about 1/2 cup hot soup into egg mixture, whisking slowly. Pour egg mixture back into pan, whisking slowly. Heat slowly (do not boil), adding more broth if too thick. Addchicken, salt and pepper, and heat thoroughly. Makes 8 cups.

Per (1-cup) serving: 230 calories, 19g fat, 150mg chol, 8g prot, 6g carbs., 0g fiber, 660 mg sodium.