Add onion, carrots, and celery. Cook for 5 to 7 minutes until softened and fragrant.
Add onion, carrots, and celery. Cook for 5 to 7 minutes until softened and fragrant.
Stir in garlic and cook for 1 minute until fragrant.
Sprinkle flour over the vegetables and stir constantly for about 2 minutes to make a roux.
Slowly whisk in chicken broth, then add milk. Continue whisking until smooth.
Add potatoes, thyme, bay leaf, salt, and pepper. Bring to a gentle boil, reduce heat, and simmer for 15–20 minutes until potatoes are tender.
Stir in chicken, peas, and corn. Simmer for 5 minutes until heated through.
Remove bay leaf. Stir in heavy cream (if using), then add parsley. Adjust seasoning and serve.