This creamy chicken soup with peas and mushrooms is delicious and rich but has a nice brightness to it thanks to fresh shelled peas, parsley, and lemon.
Cover the chicken with water in a large stock pot. Add the onion, peppercorns, mustard seeds, and garlic. Bring to a boil and then reduce heat and simmer for at least one hour.
Remove the chicken from the stock pot and transfer it to a platter. Once it's cool enough to handle, pick the meat from the bones and shred into bite-sized pieces. Discard the carcass and skin. Reserve the shredded chicken for the soup.
Return the stock to a boil and then reduce heat to medium and cook for 30 minutes until it has reduced. Turn off the heat. Scoop the garlic out of the stock pot and transfer to a bowl. Carefully pop the cloves out of the paper skin and mash them. Set aside.
Start the Creamy Chicken Soup:
Heat the neutral oil and butter in a soup pot over medium heat until frothy. Add the onion and mushrooms and cook, stirring regularly, until the mushrooms begin to brown and soften, about 7-8 minutes. Season with salt and pepper.
Add the reserved mashed garlic and the couscous to the soup pot and cook, stirring regularly until the couscous begins to turn golden brown, about 2-3 minutes.
Strain the Stock:
Place a fine-mesh sieve over the pot and using a ladle, spoon the chicken stock from the stockpot into the pot. You will need about 12-14 ladlefuls (approximately 6-7 cups).
Cook the Chicken Soup:
Add the reserved shredded chicken to the soup pot and bring to a boil. Taste and season with salt and pepper. Reduce heat and simmer for 10-15 minutes or until the couscous is about al dente.
Finish the Chicken Soup:
Add the shelled peas and cream to the pot. Simmer for 5-6 minutes or until the peas are bright green. Taste and season again to your preferences. Turn off the heat.
Prepare the Garnishes:
Combine the lemon juice and parsley in a bowl and sprinkle with salt.
To Serve:
Ladle the soup into bowls and garnish with the prepared parsley and a lemon wedge or round, if desired. Drizzle with a touch of extra virgin olive oil if preferred. Enjoy!