On Onion gravy

This method of making onion gravy I learned from my mother although I am sure it is a very common method. I have always used the original Bisto powder packaged in a box which is vegan but recently there are many more vegan products on the market which I have not got round to trying, any feedback in the comments section would be most welcome.
Put about 1 pint of water on to boil before you start to prepare the meal and add the following, 1 chopped onion, a glug of sunflower oil, a little salt and a generous amount of ground white pepper.
Leave this to boil and reduce while you cook the meal and 10 minutes before the meal is ready it has hopefully reduced to a rich tasty onion sludge which really concentrates the flavour. If it reaches the sludge stage before the meal is 10 minutes off being ready simply turn it off so it does not burn.
Mix 7/8 teaspoons of Bisto powder in a cup with just enough cold water to make it runny. Add about 3 quarters of a pint to 1 pint of cold water to the onion mix, more water makes a runnier gravy, less makes it thicker which is my preference. Put the pan on to a high heat and immediately add the Bisto mix, I plunge the cup into the pan of water and onions and get all the Bisto out of the cup as it tends to stick in the bottom of the cup so make sure you get it all out.
Once the Bisto is in the onion water and it is on the heat you must stir it constantly until it boils otherwise it will go lumpy and you don't want lumpy gravy. When it bubbles it is ready to serve.
A quicker method if you are pressed for time is to fry the chopped onion in sunflower oil and as it starts to brown add the cold water, salt and pepper and the Bisto mix and bring to a boil again stirring constantly.
I have added half a teaspoon of original Natex now and then and it adds to the savoury flavour, you could also add mustard or soya sauce to add more flavour or go crazy and add all 3. experiment and enjoy specially on a vegan roast dinner.