Onion Burger

Prep

1. Burger Buns

Cooking

1. Peel the onions and halve them if needed to fit the mandolin. Slice on the thinnest setting into a bowl. Use the safety guard.
2. Divide the beef into 4 even balls, roughly 110g each. Roll them tight in your hands so they hold their shape when smashed.
3. Preheat a flat-top BBQ or heavy-based frying pan on high until just smoking. If it’s well-seasoned you won’t need oil. If not, a light drizzle of neutral oil is fine.
4. Place the beef balls on the cooking surface with plenty of space between them. Season generously with sea salt, getting some on the cooking surface around each ball too.
5. Pile a small mountain of the sliced onions on top of each ball. Don’t be shy, they’ll cook down.
6. Lay a sheet of parchment paper over the top of one ball and use a burger press to smash straight down through the onions into the meat. Even pressure, all the way flat. Repeat with the other three.
7. Cook for 2 to 3 minutes without moving. The fat will render out, the onions on the bottom will start to caramelise, and a proper crust will build on the meat.
8. Use the flat spatula to scrape the onions off the top and pile them onto the meat side. Then flip each patty over so the onions are now underneath and cooking directly on the hot surface. Cook for another 2 minutes.
9. Lay a slice of American cheese on each patty. Move the patties to one side of the grill if you have space, and lightly toast the cut side of the buns in the same pan.
10. Once the cheese has just melted, place two patties on top of one another to make a double stack. Repeat with the other two.
11. Squeeze a stripe of American mustard onto each bottom bun. Set the double stack on top of the mustard. Add 3 pickle slices on top of the beef, cap with the top bun and serve immediately.