Add butter to a medium sauce pan over medium-low heat. Once it starts to bubble and foam, whisk in the flour and cook, continuing to stir for 3-4 minutes just until it starts to brown. Add the wine or sherry and whisk again to combine.
Add 5 cups of stock, the salt, pepper and herbs. Turn heat to high keeping a close eye for about 2 minutes. Once it starts to bubble up, return heat to medium-low and let simmer for 10 minutes. Taste and season with more freshly ground pepper and salt as desired. If you find the gravy to be too thick, add a little more stock and taste again. *If storing for future use, reserve the extra cup stock to be added before reheating.
Turn off heat and remove bay leaf, sage leaves and thyme stems or strain if needed. Allow to cool before storing in an airtight container in the fridge or freeze until ready to serve (see note below). Optional: stir in roast drippings on the day for more flavour.