Peel the onions and finely slice them into thin rings.
4 onions
In a large saucepan heat the oil or butter. On a low to medium heat fry the onions until they begin to brown. This should take between 5-10 minutes.
2 tablespoon oil
Sprinkle the sugar over the onions and fry for a further minutes for the onions to start caramelizing.
2 teaspoon brown sugar
Add in the tomato paste, stir until the onions are coated, and fry for a further 2 minutes whilst stirring throughout
2 tablespoon tomato paste
Deglaze the onions with the beer and broth and cook for about 10 minutes to further reduce the sauce. Season the sauce with salt and pepper. You can add more sugar if your beer is too bitter.
1 ½ cups stout, 1 ½ cups beef broth, salt and pepper
In a small bowl mix the corn starch/ corn flour with 2 tablespoons of water to a thick paste and add it to the gravy. The sauce should start to thicken. Season with salt and pepper to taste. Serve immediately.