Prepare the vegetables. Dice the onion, carrots and mushrooms, chop the celery, and cut the potatoes into small, evenly sized pieces.

Build the soup base. Melt the butter in a large Dutch oven or soup pot over medium heat. Add the onion, carrots, and celery. Cook for approximately 5–7 minutes, until they begin to soften.

Add the mushrooms and garlic. Continue cooking for another few minutes, allowing the mushrooms to soften and release some of their moisture.

Thicken the soup. Sprinkle the flour over the vegetables and stir until everything is coated. Cook briefly to remove the raw flour taste.

Add the stock and potatoes. Slowly pour in the chicken stock while stirring. Add the potatoes and season lightly with salt and pepper. Bring to a gentle boil, then reduce to a simmer until the potatoes are fork-tender, approximately 12–15 minutes.

Finish the soup. Stir in the shredded rotisserie chicken, peas, corn, cream, and parsley. Simmer gently for approximately 5 minutes, until everything is heated through.

Taste and serve. Adjust the seasoning as needed. Serve warm with biscuits, crusty bread, or my favorite - puff pastry!