Place turkey neck and giblets in a large saucepan; add 6 cups water and 3 1/2 cups chicken broth, carrots, onion, celery and bay leaf.
Bring to a boil and then turn down to simmer over medium heat for about 2 hours. Stock should be reduced to about 3 cups.
Strain stock into a bowl and chop the neck meat and giblets.
To make the gravy:
Melt 5 tablespoons butter in large saucepan. Whisk in 5 tablespoons all-purpose flour and continue whisking for 2 minutes.
Slowly whisk in 3 cups turkey stock, 1/4 cup cream, up to 1 cup reserved turkey pan juices and 2 tablespoons pre-baked cornbread dressing.
Simmer gravy for 5 minutes or until thickened to desired consistency, whisking frequently.
Add chopped meat and chopped hard-boiled egg and season to taste with pepper.
Notes
Adapted from Giblet Cream Gravy in Bon Appetit magazine, circa 1999: http://www.bonappetit.com/recipes/1999/11/honey-brined-turkey-with-giblet-cream-gravyGluten-free option: Use gluten-free flour and make sure if you use pre-baked cornbread dressing that has also been made gluten-free. We tested this recipe in 2023 as gluten-free, and it was delicious.