Instructions

1. Combine the chicken broth with 2 cups of water in a large saucepan. Add the chicken, sliced onion, parsley, thyme, peppercorns, and 1/2 teaspoon salt. Bring to a boil. Lower heat to medium-low, partially cover the pot, and simmer the chicken over medium heat until the meat is no longer pink, about 30-40 minutes. Take the chicken pieces out and set aside. Strain and reserve the remaining broth.
2. Melt 1 tablespoon butter in a large pot over medium heat, and saute the chopped onion, carrots, celery, and mushrooms. Continue to cook until onion is translucent, about 5 minutes. Stir in the potatoes. Add 4 cups of the reserved broth. (Save remaining broth for another use.) Reduce heat to low and simmer for 30 minutes.
3. After the chicken has cooled, shred the meat into bite size pieces using two forks. Set meat aside to add at the end.
4. With the 5 remaining tablespoons of butter, add the flour and mash with a fork to make a thick paste. Whisk in 2 cups of the cooking broth to make a thinner paste. Whisk this mixture into the large pot and continue to whisk until smooth. Add the cream and milk and stir constantly until thickened and smooth, about 10 minutes. Add the shredded chicken and peas and continue to heat another 15 minutes. Season to taste with salt and pepper.