Take the pot off the heat and whisk in the xanthan gum. Mix well to combine, then let rest for 3-4 minutes to allow it to thicken. Season with salt and pepper as needed. Serve and enjoy!
Do NOT add more xanthan gum unless you've let this gravy sit for at least 10 minutes before adding more. If you want a thicker gravy, add 1/8 tsp more xanthan gum and allow it to rest. Too much xanthan gum and your gravy will be slimy!