Melt butter in a large heavy-bottomed pot over medium-high heat. Add diced onion and minced garlic, sautéing for 2-3 minutes until fragrant and softened. This flavor foundation prevents the soup from tasting flat or one-dimensional.

Add chicken pieces directly to the pot, stirring occasionally for 4-5 minutes until the outside is sealed but meat isn't fully cooked through. This rich chicken soup technique locks in juices while building fond on the pot bottom.

Pour in chicken broth and add bay leaves, dried thyme, salt, and pepper. Bring to a rolling boil for 2 minutes, then reduce to medium heat. Let the mixture simmer gently while adding sliced carrots, diced celery, and mushroom slices.

Continue cooking for 10-12 minutes until chicken is completely cooked through and vegetables are just tender but not mushy. The creamy chicken soup recipe reaches perfect consistency at this stage without overcooking delicate ingredients.

Reduce heat to low and slowly stir in heavy cream, mixing constantly for 1-2 minutes until fully incorporated. Never boil after adding cream, or the sauce may separate and lose its silky texture.

Taste and adjust seasonings with additional salt and pepper as needed. Remove bay leaves and stir in fresh chopped parsley. Serve immediately while steaming hot.