Make red onion gravy! Fry a finely sliced onion, along with 1 tsp light brown sugar and 2 tbsp of unsalted butter over a low heat for 15-20 minutes, until starting to caramelize. Sprinkle over 2 tbsp flour and stir. Cook for 2 minutes to cook out the taste of the flour. Add in 2 cups (420ml) of hot vegetable stock (water plus 2 stock cubes), slowly, whilst stirring all the time, until the gravy thickens. Add a splash of vegetarian Worcestershire sauce and season with salt and pepper before serving.