Make the Burger Sauce: In a small mixing bowl, combine the mayonnaise, ketchup, mustard, diced gherkins, gherkin brine, onion powder, garlic powder, and smoked paprika. Stir until everything is well incorporated. Set aside – the flavours will meld together while you prepare the burgers.

Prepare the Patties: Divide the 500g of beef mince into 4 equal portions of 125g each. Gently roll each portion into a loose ball. Do not pack them tightly – the looser they are, the better the lacy edges you'll get when you smash them. Place them on a plate or tray.

Toast the Buns: Lightly butter the cut sides of your brioche buns. Place a large cast-iron skillet, griddle, or heavy-bottomed frying pan over a medium heat. Place the buns, butter-side down, and toast for 1-2 minutes until they are golden brown and fragrant. Remove and set aside.

Heat the Pan: Wipe the pan clean, add the teaspoon of vegetable oil, and turn the heat up to high. You want the pan to be seriously hot – it should be just starting to smoke lightly. This high heat is essential for a good crust.

Smash the Burgers: Working in batches of two to avoid overcrowding, place two mince balls onto the hot pan. Immediately, using a sturdy metal spatula, press down firmly on each ball until it's about 1cm thick. I find that placing a small piece of baking parchment between the spatula and the meat prevents it from sticking on the first smash.

Season and Cook: Once smashed, generously season the top of each patty with salt and freshly ground black pepper. Cook for about 90 seconds to 2 minutes. You'll see the edges start to turn deep brown and crispy.

Flip and Add Cheese: Using your spatula, carefully scrape under the patty, ensuring you get all of the caramelised crust with it. Flip the burgers over. Immediately place a slice of American cheese on top of each patty. Cook for another 60 seconds. The residual heat will melt the cheese into a glorious, gooey blanket.

Assemble Your Burger: Spread a generous layer of the burger sauce on the top and bottom toasted buns. Place the hot, cheesy patty onto the bottom bun. Add your thinly sliced onions and any other toppings you're using, like lettuce and tomato. Place the top bun on, and serve immediately.