This recipe starts when you remove the whole roasted turkey from the oven. Remove the turkey to a platter or rimmed sheet pan.
Span the large roasting pan over 2 burners and turn the heat onto medium-high. The liquid will start to sputter.
Add 1 cup of broth to the pan and using a spatula, scrape the bits from the bottom of the pan.
Refrigerate
Pour the drippings into a large wet measure or other container and refrigerate for 30 minutes (or if making ahead, you can refrigerate overnight).
Separate & Measure the Fat
After the fat has become solid on the top, scrape the fat off the top and into another container.
Measure 1/4 cup of fat and reserve 1 cup of the pan drippings for the gravy. You can refrigerate or freeze the remaining fat and pan drippings for more future gravy.
Make the Roux
Measure 1/4 cup of the fat and put it into a medium saucepan over medium-high heat. Add 1/4 cup of all-purpose flour and using a metal whisk, mix until you get an even consistency.
Add the pan drippings to the roux. Whisk together until combined.
Add 1/2 cup of the broth and whisk together until combined. If you want it thicker, simmer for longer. If you want it thinner, add more broth.
Adding Optional Ingredients
If you want add the optional extra ingredients to deepen the flavor, you can add them now. Stir to combine and simmer for a few minutes.
To Get Smooth Gravy
If you want very smooth gravy, filter the gravy through a sieve before adding to the gravy boat/container.
Fresh vs. Dry Herbs: Use this rule of thumb ratio if you do not have any fresh herbs on hand: 3 parts fresh herbs to 1 part dried herbs
Note on finished recipe amount: this recipe makes about 3 1/2-4 cups of gravy depending on how you like your gravy. If you saved the extra pan drippings and fat, theoretically, you can make much more gravy too.