Oklahoma Onion Smashed Burger Recipe

Make the sauce

In a small bowl, combine mayonnaise, ketchup, yellow mustard, sweet pickle relish, apple cider vinegar, garlic powder, onion powder, hot sauce (if using), and salt. Whisk until smooth. Taste and adjust sweet/tangy balance; refrigerate while you prepare the rest (minimum 15 minutes).

Prepare and steam-sauté onions

Slice the yellow onion into 1/4-inch rings or thin half-moons. Heat a large skillet or griddle over medium heat and add butter. When butter foams, add onions and sprinkle 1/4 tsp kosher salt. Cook, stirring occasionally, for 6–8 minutes until softened and starting to caramelize. If they start to brown too quickly, add a tablespoon of water, cover for 1–2 minutes to steam and soften, then continue cooking to desired tenderness. Remove from pan and keep warm.

Portion the beef

Divide the 1 lb ground beef into four equal portions (about 4 oz each) and loosely form into balls. Do not overwork the meat; keep them slightly sticky so they will smash well.

Preheat griddle or skillet

Heat a heavy cast-iron griddle or large skillet over medium-high heat until very hot. Add the 1 tablespoon vegetable oil and spread across the surface.

Smashed cooking

Working one or two at a time (depending on pan space), place a beef ball on the hot surface. Immediately press down firmly with a heavy spatula or a sturdy flat-bottomed metal spatula (use a folded piece of parchment or another spatula to protect your hand) to flatten the patty to about 1/4-inch thickness. Season the exposed top with a pinch of kosher salt and some black pepper. Cook undisturbed for 2–3 minutes until the edges are deeply browned and crispy.

Flip and cheese

Using the spatula, scrape under the patty and flip it. Immediately place a slice of American cheese on the hot side so it melts while the burger finishes, cook another 30–60 seconds until cooked through and cheese is melted. Repeat for remaining patties.

Steam or toast buns

Lightly steam the buns for about 20–30 seconds over simmering water using a steamer basket, or place them cut-side down on the hot griddle for 15–30 seconds to warm and slightly toast. Keep warm.

Assemble burgers

Spread about 1 to 1 1/2 tablespoons of Loose Moose sauce on the bottom bun. Place the smashed cheeseburger patty on the sauced bottom bun. Top the patty with a generous tablespoon of the cooked onions, then add about 2 tablespoons (roughly) of thin-sliced icebox pickles. Add any extra sauce on the top bun if desired. Close the sandwich and press gently to compact.

Serve

Serve immediately while hot so the edges remain crisp and the cheese is melty. Provide extra pickles and sauce on the side if desired.