Vegetarian Gravy

[suedonim]

I'm looking for a recipe for a really tasty vegetarian gravy for Christmas dinner. Most of us will be having turkey etc but there will also be two vegetarians present. My veggie gravy is always too bland so any idea are v welcome!

Fry onions, peppers, mushrooms (& Tomato if you want - I don't usually)
Add flour
Add stock (& a veggie stock cube if it needs it)
Add gravy browning (or make your own if you want)
You can liquidise it

Mmmm, sounds tasty and also easy to do, thanks!