- 2 tbsp olive oil.
- 1 onion, finely chopped.
- 2 celery sticks, finely chopped.
- 1 large carrot, finely chopped.
- 1 large leek, finely chopped.
- 1 tbsp plain flour.
- 500ml vegetable stock (made from good-quality vegetable bouillon).
- 1 tbsp soy sauce.
- Heat olive oil in a roasting tin or frying pan over a medium heat. Add the onion, celery, carrot and leek. Cook for a good 30 minutes, until the vegetables are really soft and beginning to turn a golden brown.
- Stir in plain flour and cook for a couple of minutes, then gradually add vegetable stock. Simmer for a couple of minutes, then add soy sauce. Strain the gravy through a fine sieve, pressing the vegetables into the sieve with the back of a wooden spoon to release the flavours. Season to taste, then serve in a warmed jug