- In a mini chopper blend the bacon rashers until it is minced. 
- Add the minced bacon to the minced beef and the mustard, season with salt and pepper. 
- Roll the meat into 100g balls. It should make at least 8 burgers. 
- Place the rolled meat in the fridge to rest while you make the sauce 
- In a bowl to make the sauce, mix the mustard, ketchup, mayonnaise and diced gherkins.  
- Heat up a cast iron pan with a drizzle of oil. Remove the burgers from the fridge. Place the meat in the pan and press down with a spatula. As the are thin burgers they will take a minute to cook on each side. After you have turned over the burger place the cheese on top. 
- Toast the bun. Spread some sauce on the bottom followed by the lettuce and tomato. place on the 4 burger patties followed by the finely slice onions and top with more sauce.