In a medium saucepan, add fresh herbs to stock and bring to a boil. Turn down and simmer for about 15 minutes. (Roasted veg stock is nice because it offers not only a deep colour but some nice flavours, as well). Discard herbs.
In another medium sauce pan, melt 6 tbsp butter, add 1/2 cup flour and whisk over medium heat until golden brown and shiny. Be careful to not let it burn!
Slowly add stock and keep whisking off and on for about 10 minutes until the desired consistency is reached.
Stir in Worcestershire and season with salt and pepper. If the gravy is too thick, add a bit of stock and stir for about 30 seconds. Store in the fridge (for up to five days) until ready to use.
Note: start with 1 litre of stock to end up with 900 ml (4 cups) of gravy.