Melt butter in a medium saucepan over medium heat. Add onions, celery, carrot, thyme, and bay leaf, and cook until the onions are soft and lightly browned.
Add giblets to the pan and add water until the ingredients are just covered
Bring this mixture to a boil, then reduce the heat and simmer, covered, for an hour.
After an hour, strain this mixture into a vessel and set it aside. Reserve the giblets and discard the rest of the ingredients.
Pull as much meat from the neck as you can and chop it nice and fine, along with the rest of the giblets.
Make a roux using your pan drippings and the flour: Heat the pan drippings over medium heat, add finely diced giblets, and cook for about 2 minutes.
Start whisking flour into the pan drippings, 1 teaspoon at a time, until a thick paste forms. Cook this paste over medium-low heat until it is golden brown and smells toasty like a biscuit.
Add 1/4 cup of the strained liquid to the roux, whisking thoroughly between each addition, and cook, whisking constantly, until the mixture is thick and smooth (like gravy!). Add black pepper and salt to taste.
Cara Nicoletti is a butcher and writer living in Brooklyn, New York. Cara started working in restaurants when she moved to New York in 2004, and was a baker and pastry chef for several years before following in her grandfather and great-grandfathers' footsteps and becoming a butcher. She is the writer behind the literary recipe blog, Yummy-Books.com, and author of Voracious, which will be published by Little, Brown in 2015. She is currently a whole-animal butcher and sausage-making teacher at The Meat Hook in Williamsburg.