In a large pot, heat a tablespoon of olive oil over medium heat. Add diced onions, carrots, and celery, sautéing them for about 5–7 minutes until they soften and become translucent.

Next, incorporate sliced mushrooms into the pot, stirring them in well. Cook the mushrooms for another 5 minutes.

Stir in the shredded rotisserie chicken and pour in 6 cups of chicken broth. Increase the heat and bring the mixture to a boil.

After the broth comes to a boil, season the soup with fresh thyme, salt, and pepper to taste. Reduce the heat to a low simmer and cover the pot.

After 20 minutes, remove the pot from heat and stir in freshly chopped parsley.

Ladle the soup into warm bowls and serve it hot.