For caramelised onions, heat a wide based pan and melt the butter until it starts to foam. Add the onions and cook slowly constantly stirring so the onions do not stick (approx 15mins) until onions are dark brown in colour and softened. Season to taste. Keep warm
Divide mince into 150g patties. Heat a large pan with oil and season each patty with salt. Cook patties until nice even brown colour flipping once or until your liking and top with cheese.
Grill bacon in a pan or on a char grill until caramelised
Spread bottom hamburger bun with mayonnaise, followed by some caramelised onions. Top with the patty, followed by the bacon, pickles and tomato sauce and finally lace the top bun on top.