Oklahoma Onion Smash Burger

This Oklahoma smash burger is a crispy-edged, juicy, diner-style burger with thin-sliced onions smashed right into the patty so they caramelize in the beef as it cooks. Finish it with melty cheese and a homemade burger sauce, and it tastes like a real burger joint burger at home. It’s simple, fast, and ridiculously satisfying. If you’ve made my Onion Wrapped Flying Dutchman Burger, you’re going to love this smash burger recipe with onions, too.

Why You'll Love This Smash Burger Recipe with Onions

The Oklahoma onion smash burger is all about texture and flavor. Smashing the beef gives you those crispy, lacy edges, and the onions basically cook into the patty, turning sweet, jammy, and a little caramelized right where the meat is crispiest.

Then the burger sauce ties everything together with that classic tangy-sweet bite that makes it taste like a real diner burger instead of “burger at home.” And the best part is how fast it is. Once your pan or griddle is hot, these cook in minutes, which makes them perfect for weeknights, game day, or anytime you want a burger that actually hits.

Ingredients You'll Need

For the Burgers:

• 1.5 pounds ground beef (80/20)
• 2 large onions, thinly sliced
• 12 slices American cheese
• Brioche buns
• Pickles (optional, but highly recommended)
• Salt

For the Burger Sauce:

• ½ cup mayo
• 3 tablespoons ketchup
• 2 tablespoons yellow mustard
• 1 ½ tablespoons sweet relish
• 1 ½ tablespoons hot sauce
• 1 teaspoon black pepper
• 1 teaspoon kosher salt

Ingredient Notes That Make This Burger Better

• 80/20 beef: You need fat for smash burgers. Lean beef won’t crisp the same and can dry out fast.
• Super thin onions: Thin matters. A mandolin is ideal. Thin onions soften quickly and caramelize into the patty instead of staying raw.
• American cheese: Melts perfectly and gives that classic smash burger vibe. It’s not fancy, it’s correct.
• Brioche buns: Soft and slightly sweet, perfect for smash burgers. Just make sure you toast or steam them so they don’t fall apart.

How to Make a Smash Burger with Onions

Step 1: Prep the onions (don’t skip this)

Slice onions very thin with a mandolin. Toss with kosher salt and let sit 20 minutes to draw out moisture. Squeeze out as much liquid as possible and set aside. This step helps onions cook faster on the burger and prevents steaming.

Step 2: Form and chill the beef balls

Divide ground beef into equal balls, about ¼ pound each. Refrigerate 15 minutes to firm up. Cold beef smashes cleaner and helps you get a better crust.

Step 3: Heat the griddle

Preheat your griddle on high for about 10 minutes. Lightly oil if needed. You want it screaming hot. That’s how you get the crisp smash crust.

Step 4: Make the burger sauce

Whisk mayo, ketchup, mustard, relish, hot sauce, salt, and pepper until smooth. Set aside.

Step 5: Smash and onion-top

Place beef balls on the griddle. Immediately pile a generous handful of drained onions on each. Smash as thin as possible using a spatula or burger press. Season with salt. Tip: Use parchment between spatula and onions to prevent sticking.

Step 6: Cook, flip once, and add cheese

Cook about 4 minutes until the edges look deeply browned and you can see crust forming. Flip, season the other side, and cook 2 minutes more. Add a slice of American cheese to each patty.

Step 7: Steam the buns

Place the top bun directly over the cheese. Stack the bottom bun on top of the top bun. Close the lid for a couple of minutes to steam and soften.

Step 8: Assemble and serve

Remove buns. Spread burger sauce on the bottom bun and add pickles if using. Add one or two patties. Top with the top bun and serve immediately.

Pro Tips for Crispy Smash Burger Crust

• Get the surface hot enough. High heat is non-negotiable. If your griddle isn’t hot, the burgers won’t crust, they’ll steam.
• Smash once, hard. Smash immediately and don’t re-smash later. Pressing again forces juices out and can make patties dry.
• Use a stiff metal spatula or burger press. Thin patty = crispy edges. A flimsy spatula won’t do it.
• Don’t crowd the griddle. If you crowd, you drop the temp and lose crust. Cook in batches if needed.
• Scrape under the patty when flipping. The crust sticks to the griddle. Use a firm scrape to keep the crust on the burger instead of leaving it behind.
• Onion moisture matters. If onions are too wet, they steam the burger. Salting and squeezing is what makes them caramelize into the patty.

What to Serve With Onion Smash Burgers

These Oklahoma onion smash burgers are classic diner-style, so the best sides are simple, salty, and crunchy.

• Fries: Regular fries or thin smash burger-style fries are the perfect match, especially with extra burger sauce for dipping. These Louisiana Voodoo Fries or Five Guys seasoned fries are also delicious.
• Onion rings: You can’t go wrong here. Crispy onion rings + a smashed onion burger is a combo that just makes sense.
• Potato chips: The easiest side. Grab a bag of your favorite chips and you’re done, and the crunch goes great with a juicy burger.
• Coleslaw: A cold, crisp slaw balances the rich burger and cuts through the grease in the best way. This Popeyes coleslaw is a perfect pair.
• Pickles on the side: Extra pickles are always a win. They add tang and keep the meal feeling fresh.

Onion Smash Burger Storage and Reheating Tips

Smash burgers are best fresh (those crispy edges are the whole point), but leftovers still work if you reheat them the right way.

• Refrigerator: Store cooked patties in an airtight container in the fridge for up to 3 days. If you can, store the patties separately from the buns and toppings so nothing gets soggy.
• Reheating: Reheat patties in a skillet over medium heat until warmed through. Add a tiny splash of water to the pan and cover for 30 seconds if you want the cheese to re-melt without drying the meat. Skip the microwave if you want to keep any crisp texture.
• Burger sauce: Store the burger sauce in an airtight container in the fridge for up to 7 days. Give it a quick stir before using since it can thicken slightly as it sits.

Oklahoma Smash Burger FAQs

More Burger Recipes To Try Next

• Grilled cheeseburger
• Smash burger tacos
• Lamb burgers
• Mushroom swiss burger
• Brisket burgers
• Garlic parmesan cheeseburger bombs