First Step: Prepare IngredientsStart by shredding rotisserie chicken into bite-sized pieces. Slice the mushrooms thinly, dice the onion, finely chop celery, and crush the garlic cloves. Set ingredients aside for easy access during cooking.

Second Step: Sauté AromaticsHeat a splash of olive oil or a knob of butter in a large pot or Dutch oven over medium-high heat. Add diced onion and celery, sautéing until soft and translucent (about 3-4 minutes). Stir in crushed garlic until fragrant, approximately 1 minute.

Third Step: Cook MushroomsAdd sliced mushrooms to the pot and cook for 5-7 minutes, stirring occasionally, until they become golden brown and release their moisture. This step intensifies their earthy flavor and builds soup depth.

Fourth Step: Build the Soup BaseSprinkle in fresh thyme and stir briefly. Pour in chicken broth and heavy cream, bringing the mixture to a simmer. Allow the soup to cook for 5 minutes to meld flavors and thicken slightly.

Fifth Step: Add Chicken and SpinachStir shredded rotisserie chicken and chopped spinach into the broth. Continue simmering for an additional 5 minutes or until the chicken is warmed through and spinach is tender but vibrant.

Final Step: Season and ServeSeason the soup with salt, black pepper, and a squeeze of fresh lemon juice to brighten the flavors. Serve the rotisserie chicken mushroom soup hot, optionally with crusty bread or over cooked rice for a complete meal.