Serves 4 – Prep: 40 mins
Start by making the burger patties: mix all the ingredients in a bowl and shape 4 burger patties with your hands. Put on a plate and set aside.
Peel and slice the onions. Heat 2 tablespoons of oil in a frying pan and fry the onions with a pinch of salt for 8 minutes over a medium heat until melting. Take off the hob and stir through 4 tablespoons of barbecue sauce. Transfer into a bowl and set aside.
Wipe clean the frying pan. Cut open the burger buns and toast each cut-open side until lightly browned.
Melt a slice of raclette cheese in the pan until bubbly. Place a burger top onto the cheese, then take out of the pan and leave to cool with the cheese facing upwards. Repeat with the remaining 3 burger buns.
Heat 2 tablespoon of oil in the frying pan and fry the burger patties for 3 minutes, covering the pan with a lid. After 3 minutes, turn over the burger patties and fry for another 2 minutes with the lid on. After 2 minutes, take off the lid and brush the top of the patties with mustard, then turn them over and top each with a slice of raclette cheese. Cover the pan again and fry for another minute.
Spread a tablespoon of barbecue sauce onto each bottom burger bun. Top with a bit of chopped salad leaves, then sit a burger patty on top. Top with a tablespoon of onions, then lay a slice of ham on top, followed by sliced gherkins. Top with a parmesan-crusted burger bun in the end and serve immediately.