In a large pot over medium heat, drizzle about two tablespoons of olive oil. Allow the oil to shimmer before adding the chopped onions. Sauté the onions for 3-4 minutes until they become translucent, stirring occasionally.

Incorporate the minced garlic and sliced fresh mushrooms into the pot. Cook this mixture for about 5-7 minutes until the mushrooms turn golden brown.

Pour in about 4 cups of vegetable broth and add the shredded rotisserie chicken. Stir well, bringing the mixture to a gentle boil and warming through for around 5 minutes.

Lower the heat to a simmer and mix in half a cup of heavy cream, along with fresh thyme, salt, and pepper to taste. Simmer gently for about 10 minutes.

Adjust seasoning if needed and serve the soup hot, ideally with a side of crusty bread.