In a large Dutch oven or heavy bottomed soup pot, melt the butter over medium heat. Add the diced onions, carrots, and celery. Cook these for about 5 to 7 minutes until they begin to soften and become fragrant.

Stir in the cubed potatoes and minced garlic. Continue cooking for another 2 minutes.

Sprinkle the flour over the vegetables. Stir constantly for 1 to 2 minutes to cook out the raw flour taste. The vegetables should be well coated in a thick paste.

Slowly pour in the chicken broth while whisking or stirring vigorously to avoid lumps. Bring the mixture to a gentle boil, then reduce the heat to low. Cover and simmer for 15 minutes or until the potatoes are fork tender.

Stir in the shredded chicken, heavy cream, frozen peas and corn. Add the thyme, salt, pepper, and poultry seasoning. Let the soup simmer uncovered for another 5 to 10 minutes to allow the flavors to harmonize and the soup to thicken beautifully.

Taste your soup. Adjust the salt and pepper to your preference. If you like a thicker consistency, you can mash a few of the potatoes against the side of the pot.