Step 1

Heat the air-fryer to 200C. Cook the bacon for 8-9 mins, turning once, until crisp and browned, then transfer to kitchen paper.

Step 2

Season the mince with salt and pepper then quickly shape into 4 even-sized balls, taking care not to over-handle the meat. Place a ball on a sheet of baking parchment, then using a flat meat mallet or a potato masher, flatten the balls into a 1cm-thick patty – they need to be wider than the bun you’re serving them on as they will shrink a little during cooking. Repeat to make 4 burgers.

Step 3

Air-fry the burgers for 8-10 mins, turning once until browned and completely cooked through. Lay a slice of cheese on each burger then top with the crispy bacon. Return to the air-fryer for 1 min until the cheese has melted.

Step 4

Split open the buns and arrange the lettuce and tomatoes on the bases. Top with the smash burgers and garnish with sliced gherkins, a sprinkle of crispy onions and your choice of sauce.