Oklahoma Onion Smash Burger

How to Make a Oklahoma Onion Smash Burger

If you’ve ever wanted to make the real thing when it comes to Oklahoma Onion Smash burgers, this recipe breaks down everything you need—from the thin-sliced onions to the crispy edges that make this fried onion burger legendary.

This classic Oklahoma onion burger features heaps of onions smashed directly into the beef, creating unmatched flavor, texture, and that signature crust. Today, burger fans everywhere recreate this Oklahoma style onion smash burger because the crispy edges, melty cheese, and sizzling onions combine into one of the best burgers you’ll ever make at home.

This recipe uses simple ingredients, a cast iron skillet or flat top, and a very stiff spatula so you can master the iconic smash technique. Whether you’re cooking on a Blackstone griddle grill, a hot griddle, or a cast iron pan, these Oklahoma Smashburger’s are incredibly easy and unbelievably delicious.

Ingredients You Need for Authentic Oklahoma Onion Smash Burgers

To make true Oklahoma onion burgers, you only need a handful of ingredients from the grocery store:

• 1-pound 80/20 ground beef
• 2 large yellow onions, thin sliced
• 4 slices American Cheese
• 4 Brioche Burger Buns
• 2 tbsp favorite burger seasoning
• 1 tbsp mayo (for toasting buns)

Burger Sauce

• ½ cup mayo
• 1 tbsp ketchup
• 1 tbsp yellow mustard
• 1 tbsp sweet relish
• 1 tsp garlic powder
• 1 tsp smoked paprika
• 1 tbsp apple cider vinegar

This burger sauce brings the best flavor, perfect balance, and classic burger-shop taste. It’s similar to a classic burger scholar style sauce but with a little extra tang from the vinegar.

How to Make Oklahoma Onion Smash Burgers

Prep: Slice the Onions Thin (Super Thin!)

The key to any real oklahoma onion burger is the thin-sliced onions—the thinner the better. You can use:

• A mandolin
• A sharp knife
• A meat slicer

Your goal is paper-thin onions so they caramelize quickly and fuse into the beef patty during the smash.

Form the Burger Balls

Divide the ground beef into 4 oz balls (¼ pound each). Gently roll them into even burger balls—don’t compress too hard or they’ll lose their smash ability. These will become your thin burgers when you flatten them with the heavy spatula or grill press.

Make the Burger Sauce

Combine mayo, ketchup, yellow mustard, sweet relish, garlic powder, smoked paprika, and apple cider vinegar in a small bowl. Mix until smooth.
This sauce goes on the top of the burgers or on the bottom bun depending on your preference.

Smash the Burgers (The Best Part)

Heat your cast iron skillet, Blackstone flat top, or griddle to medium-high heat. Place each burger ball onto the hot cooking surface. Immediately pile a generous number of thin onions onto the burger balls.

Now take your very stiff spatula, burger smash tool, or grill press and smash straight down until the burgers reach their thinnest setting. This creates:

• Extra crispy edges
• Maximum surface contact
• Ultimate onion fusion into the beef fat

Season the top of each patty with your favorite burger seasoning.

Flip and Add Cheese

Cook for 3–4 minutes until deep brown. This is where the onions fry directly in the beef fat and become golden, crispy, and sweet.

Flip the burgers, then immediately add a slice of American cheese to each patty.

Cook for another 1–2 minutes, then remove from the skillet.

Toast the Buns

Spread mayo (not butter!) onto the inside of your brioche buns. Mayo helps achieve a perfectly toasted top bun and bottom bun because the oil content browns more evenly.

Toast on the griddle until golden brown.

Assemble the Oklahoma Onion Smash Burgers

Add your cheesy fried onion burger patty to bottom bun, and a spoonful of sauce on top. Place the top bun back on then enjoy!

If you’re feeling extra authentic, add:

• Pickles
• Thin mustard smear
• Hot sauce

And now you’ve got the true Oklahoma Onion Smashburger—crispy, rich, smoky, and bursting with onion flavor.

Why These Smashburger’s Taste So Good

The combination of:

• Beef fat
• Thin onions
• High heat
• Smash technique

…gives you the ultimate crispy edges and rich flavor you can’t get from a thick patty. This is the best way to make a diner-style burger at home.

Final Tips for the Best Oklahoma Onion Smashburger

• Smash early, not late
• Slice onions as thin as possible
• Use a stiff spatula
• Don’t flip too soon
• Let the cheese melt fully
• Always toast your buns

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