Use gravy browning judiciously, otherwise the dish will become unattractively brown. If you cannot obtain ... dry-roasted plain flour or browned onions, depending on the dish you are colouring.
Flour-based gravy starts with a roux ... Cook, stirring constantly, until the mixture is light brown, about 3 minutes. Slowly whisk in the stock, whisking vigorously to combine and avoid lumps.