Ingredients

Step by step

1. Combine 2 tablespoons of mayonnaise with the mustard and Worcester sauce in a bowl. Add the beef and mix until just combined. Separate the mixture into 4 equal portions and gently shape into balls. Between sheets of baking paper, press each ball so they’re a bit wider than the buns. Use your fingertips to create a divot in the centre of each patty. Slide the patties onto a large plate, still on the paper, and chill for 30 minutes.
2. Spread the cut sides of the brioche buns with the remaining mayonnaise. Heat a large frying pan over a medium heat and, in batches, toast the buns, mayonnaise side down, until golden, about 2 minutes. Flip and toast for a further 30 seconds. Set aside.
3. Remove the patties from the fridge and season well with the sea salt and freshly ground black pepper – this creates a crust. Grease a frying pan with half the oil and place over a high heat. When very hot, add two patties, divot-side up, pressing into the pan. Cook undisturbed for a few minutes until the edges start to become deeply browned. Flip the patties, press into the pan again then top with the cheese slices. Reduce the heat and cover with a lid. Cook for 1 minute or until the cheese has melted. Transfer to a plate and cover loosely. Wipe out the pan and repeat with the remaining oil and burgers.
4. Layer the lettuce, tomato, onion and gherkins on each bun base. Add the patties, drizzle with the mustard-mayo sauce and add the top bun.