I’ve been doing this for years as there never seems to be enough gravy. I take the neck, tail, and clip off the end of the wings. I roast them so they’re very brown. Then, I simmer them in store-bought chicken broth and add some sage stems. The broth totally picks up the flavor of the turkey. You can then then make a roux from butter and flour and start adding the hack turkey broth. It’s a very simple method and folks love my gravy.
Here’s the roasted parts. I’ve not made the broth yet but you get the idea.

Here’s the roasted parts. I’ve not made the broth yet but you get the idea.