1Preheat oven to 200°C. Finely slice the red onion. Thinly slice the tomato.
2Combine the beef mince and Italian herbs in a bowl and season with salt and pepper. Shape the beef mixture in to two patties. Set aside.
3Heat a drizzle of olive oil in a frying pan over a medium heat. Add the red onion and cook, stirring, until soft. Add the balsamic vinegar, warm water and brown sugar and simmer until the liquid thickens. Season. Transfer to a small bowl and set aside, covered with aluminium foil.
4Grate the Cheddar cheese and place in two even piles the same diameter as the buns. Bake for 10 minutes or until the cheese has melted in the middle and is crisp at the edges. Place the buns in the oven for the last 5 minutes to heat through.
5Meanwhile, cook the beef patties for 4-5 minutes on each side or until cooked through. Build the burgers once all components are cooked.