Shred the rotisserie chicken and set aside.

Chop the onion, celery, and garlic. Slice the mushrooms. Wash and roughly chop the spinach.

Heat the olive oil in a large pot over medium heat. Add the chopped onion and celery. Cook for 4–5 minutes, stirring occasionally, until the vegetables soften.

Then add the crushed garlic and cook for about 1 minute until fragrant.

Add the sliced mushrooms to the pot. Let them cook for 7–8 minutes, stirring now and then, until they release their moisture and start to brown. This step deepens the mushroom flavor. Many similar recipes emphasize sautéing mushrooms first to build umami.

Stir in the fresh thyme and the pinch of chili flakes. Let them mingle with the mushrooms and aromatics for about a minute.

Slowly pour in the chicken stock while stirring to de-glaze the pot and combine everything. Bring the soup to a gentle simmer.

Once the stock is simmering, add the shredded rotisserie chicken. Let it warm through, about 5 minutes.

Turn the heat down to low. Slowly stir in the heavy cream (or half-and-half). Be careful not to raise the heat too high — you don’t want the cream to boil or separate.

Then add the chopped spinach, and stir until it has wilted.

Taste your soup. Add salt, pepper, and more chili flakes if you like. Because rotisserie chicken and stock can have varying saltiness, this step is key.

Ladle the soup into bowls. You can garnish with extra thyme, a little cracked pepper, or even a drizzle of olive oil.