In a medium saucepan on a low heat, add the butter, miso, onion powder, dried thyme and soy sauce.
As the butter melts, stir the ingredients to combine.
Add the flour, continuing to stir until the ingredients form a thick paste.
Add the vegetable stock about ⅓ cup at a time, stirring well to ensure it mixes thoroughly into the paste before adding more (this will help you avoid lumps by adding too much liquid too quickly).
When all liquid is added, increase the heat slightly until the gravy is bubbling gently.
Simmer for 20 minutes to allow the thyme to infuse the gravy and the liquid to thicken. If at any point the gravy becomes too thick, simply add a little more water to thin it.
Serve with potatoes, nut roast or your favourite vegetable side dish!