Add the drippings from the pan (remove whole herbs, onions, oranges and garlic) to a gravy fat separator cup to skim off the fat when poured. OR if you don’t have one, add the drippings to a large freezer bag and allow the fat to separate to the top. Seal the bag and hold over a 3+ liquid measuring cup so that one bottom corner tip is facing down into the measuring cup like a spout. Make a small cut in this corner with scissors. The bottom liquid will flow through the cut, stop when you reach the fat. Add enough chicken broth to the drippings in the measuring cup to equal 2 1/2 cups.
Add 3 tablespoon unsalted butter and ONE tablespoon reserved Herb Butter to a large saucepan and melt over medium heat. Add the flour and cook for 3 minutes, whisking constantly.
Reduce heat to low and slowly whisk in the combined 2 1/2 cups drippings/broth. Bring to a simmer until thickened to desired consistency, whisking constantly. If it becomes too thick at any point, whisk in additional broth.
The gravy will vary from turkey to turkey because we are using the dripping from a pre-brined turkey, so, the amount of extra seasonings relies on YOU. Taste and add additional reserved butter if desired for more flavor. If the gravy needs more salt, I suggest starting with chicken bouillon, 1/4 teaspoon at a time (up to 1 teaspoon), before salting to taste. Season with pepper to taste.