In a large pot, combine the flour, cornstarch and stock/broth using a whisk. Add all other ingredients (spices), and whisk well to combine.
Turn on the heat and bring the gravy to a boil, whisking often. Once the gravy boils, reduce the heat just enough to keep it at a low boil. Not a simmer.
Boil the liquid down until it's about half gone. (This can take about 20-30 minutes or more). Whisk frequently. Adjust spices to taste. Remove from heat, allow to cool slightly and transfer to a serving container.
Please note that the nutrition data below is a ballpark figure. Exact data is not possible.