Remove your turkey from the oven once it is fully cooked. Use a spoon or a baster to collect as much liquid as possible. You may need to tilt your roasting pan a little bit, but be careful not to let your turkey go sliding anywhere.
Transfer all of the liquid you can collect to a large pyrex glass measuring cup. Allow to sit out for a few minutes. While it cools, the fat will rise to the top and the stock will separate to the bottom.
Measure out 3 tbls. of fat and add it a large saucepan. Melt the fat back down on medium heat and add in 5 tbls. of flour. Whisk together for a minute or two as it thickens and the floury taste cooks off.
Take one cup of the defatted turkey stock and begin to slowly add it in, whisking continuously. It will start out pretty thick.
At this point I begin to add in unsalted chicken stock to thin it out the rest of the way. The reason I use this, is that the stock from the turkey drippings can be pretty salty. Taste as you go, and if you feel like it needs more turkey flavor and it’s not overly salty, add in the liquid drippings! Keep adding either liquid until you have reached your desired consistency.
Season with pepper, to taste.