Oklahoma Onion Burger

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Oklahoma Onion Burger

Key Steps

Paper-thin onions

The onions need to be sliced as thin as you can get them, thin enough that they’ll caramelise in the same time it takes the burger to cook. Too thick and they’ll still be raw when the beef is done. I use a mandolin to achieve this. Set it to the thinnest setting, halve the onions and slice them into wispy shreds. Use the safety guard if you value your fingertips. You need more onions than you think, roughly one large brown onion per patty.

Smash into the onions, not the pan

The technique that makes this burger different from a regular smash burger. Don’t smash the beef ball onto the pan first. Pile a mountain of sliced onions on top of each beef ball, then lay a sheet of parchment paper over the top and smash down through the onions into the meat. This presses the onions into the surface of the beef so they cook together, and the fat rendering out of the patty caramelises the onions from underneath.

Ingredient Notes

Beef mince:

Look for a fattier mince for this burger, around 80/20 or even 70/30 (lean to fat). The extra fat renders out and helps the onions caramelise underneath. If you can, grind your own from chuck with a bit of brisket or ribeye trim mixed in. Otherwise a good butcher’s mince is your best bet.

Brown onions:

Also called yellow or sweet onions in the US. Roughly one large onion per patty is the rule of thumb. Slice them paper-thin on a mandolin, not a knife. The thinner they are, the faster they caramelise, which is what makes the whole recipe work in the short cook time.

American cheese:

The yellow, plastic-wrapped kind. I know it gets ridiculed but for this burger it’s non-negotiable. It melts smoothly and evenly across the patty in a way aged cheddar or blue cheese can’t, and the flavour is exactly what you want alongside the sweet onions and mustard.

Potato buns:

Soft, slightly sweet, and sturdy enough to hold a double stack without falling apart. Brioche buns work too but can be a touch dense. A regular soft burger bun will do in a pinch. A quick toast on the cut side helps the bun hold up to the juices.

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Ingredients

440g beef mince (80/20 meat to fat)
3 brown onions
4 soft potato buns
4 slices American cheddar
6 pickle slices
American mustard to serve
sea salt

Equipment

Japanese mandolin
Chopping board
Chef’s knife
Kitchen scale
Flat-top BBQ or heavy-based frying pan
Burger press or protein press
Parchment paper
Flat spatula (a big wide one)
Tongs

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Directions

PREP YOU INGREDIENTS

Peel the onions and halve them if needed to fit the mandolin. Slice on the thinnest setting into a bowl. Use the safety guard.
Divide the beef into 4 even balls, roughly 110g each. Roll them tight in your hands so they hold their shape when smashed.

COOK THE BURGERS

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.
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.
Pile a small mountain of the sliced onions on top of each ball. Don’t be shy, they’ll cook down.
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.
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.
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.

BUILD AND SERVE

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.
Once the cheese has just melted, place two patties on top of one another to make a double stack. Repeat with the other two.
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.

Notes

Steam or toast the buns

Once the cheese has melted, pop the bottom bun on top of the patty and let the residual heat and steam soften it. It’s what George Motz does and it’s genuinely great. If you prefer, a light toast on the cut side gives more structure, especially if the burgers might sit for a minute before serving. Either works.

Storage

Burgers are a serve-fresh dish. Leftover cooked patties can go in the fridge in an airtight container for up to 2 days, but the onions will lose their crisp caramelised texture. If you’re prepping ahead, slice the onions up to 4 hours in advance (they’ll oxidise fast if left much longer) and cook the patties fresh at serve time. Don’t freeze.

FAQs

Do I need a mandolin?

Practically, yes. You could try to slice the onions paper-thin with a very sharp knife but it’s slow and inconsistent, and even a slightly thicker slice won’t caramelise fast enough to keep pace with the burger. A basic Japanese mandolin is under $30 and pays for itself across dozens of recipes. Use the guard.

Do I need a burger press?

No, any heavy flat object works. A cast-iron pan bottom, a heavy pot, even a flat metal spatula pressed down with the heel of your hand. The point is even pressure across the whole patty. Always use parchment paper between the press and the beef so nothing sticks.

Can I make this without a BBQ or flat top?

Yes. A heavy cast-iron pan on the stovetop over high heat does the same job. Make sure the pan is properly hot before the beef goes in, and don’t crowd it. Work in batches if your pan can’t hold 4 patties comfortably.

Can I skip the American cheese?

You can, but this burger really wants American cheese. If you can’t get it or don’t want it, thinly sliced good-quality cheddar will work but it won’t melt as smoothly. Skip aged or crumbly cheeses like blue or feta, they don’t melt into the patty the same way.

Can I use a different bun?

Soft is the main thing. Potato buns are ideal because they’re both soft and sturdy. Brioche buns work but are a touch denser. Regular burger buns are fine. Skip anything with too much crust or chew, this burger wants a pillowy bun that gives easily.