Sauté the Vegetables – Melt butter in a large pot over medium-low heat. Add chopped onion, carrots, and celery, cooking for 6-8 minutes until softened. Stir every minute. Add minced garlic for the last 30 seconds and mix well.
Make the Roux – Sprinkle in flour and stir until vegetables are coated. Cook for 1 minute to remove the raw flour taste.
Add the Broth & Potatoes – Pour in chicken stock, milk, sweet potatoes, salt, pepper, and thyme. Stir well. Bring to a gentle boil, then reduce heat and let it simmer for 15-20 minutes, stirring occasionally, until the potatoes are tender.
Incorporate the Chicken & Greens – Mix in shredded chicken, frozen peas, parsley, and optional spinach. Simmer for 5 more minutes until heated through. Adjust seasoning to taste.
Serve & Enjoy – Remove from heat and ladle into bowls. Pair with a biscuit, garlic bread, or toasted bread for the ultimate comforting meal.