Heat a large pot over medium heat and add the olive oil.

Add the chopped onion and sauté until translucent, about 3 to 4 minutes.

Add the minced garlic and sliced mushrooms. Cook, stirring occasionally, until the mushrooms release their liquid and turn golden brown, about 5 to 7 minutes.

Pour in the vegetable broth and bring it to a gentle simmer.

Add the shredded rotisserie chicken and stir to combine.

Reduce the heat to low, stir in the heavy cream and thyme, and season with salt and pepper.

Let the soup simmer gently for 10 minutes so the flavors meld.

Taste and adjust seasoning with more salt, pepper, or a pinch of thyme. If the soup is too rich, thin it with a splash of extra broth.

Ladle into bowls and garnish with extra thyme leaves or cracked black pepper before serving.