Sonic Double Smasher Burger Copycat Recipe

This sonic double smasher burger copycat brings the flat-smashed, crispy-edged double patty stack straight to your stovetop, no drive-through required.

It’s one of those burgers where the beef is actually the star, because smashing it thin against a hot cast iron creates a crust you can’t get any other way.

Why I Love This Recipe

The sear on a smash burger is different from a regular grilled patty. The flat contact with screaming-hot metal gives you lacy, caramelized edges and a thin patty that stays juicy in the middle.

I keep coming back to this version because the double stack with American cheese melted between both patties makes every bite consistently cheesy, not just the top.

The sauce takes about 2 minutes and does a lot of the heavy lifting: tangy, a little sweet, and just creamy enough to hold the whole thing together.

Recipe Ingredients

• 8 oz (225g) 80/20 ground beef – Two 4 oz balls per burger; the fat content is what gives you those crispy edges
• 2 plain burger buns – Soft potato buns or standard brioche both work; avoid thick artisan buns that overwhelm the thin patties
• 4 slices American cheese – Melts into the patties rather than sitting on top; white cheddar is a decent swap but won’t get as gooey
• 1 tbsp vegetable oil – High smoke point matters here; canola works too
• 1 tsp kosher salt – For seasoning the beef balls just before smashing
• 1/2 tsp black pepper – Coarsely cracked if you have it
• 2 tbsp mayonnaise – The base of the sauce
• 1 tbsp yellow mustard – Bright and tangy; gives the sauce its backbone
• 1 tbsp ketchup – A little sweetness to balance the mustard
• 1 tsp pickle brine – From a jar of dill pickles; adds a sharp hit of acid
• 1/2 tsp garlic powder – Goes into the sauce
• 1/2 tsp onion powder – Goes into the sauce
• 8 dill pickle chips – The thin crinkle-cut kind work well here
• 1/4 small white onion – Finely diced; raw on the burger for crunch and bite
• 1 cup shredded iceberg lettuce – Stays crisp and cool against the hot patties
• 4 slices tomato – Cut about 1/4 inch thick

Variations / Substitutions

• Single patty – Use 1 ball of beef per burger and reduce cook time by about 1 minute per side; you lose some of the layered cheesiness but it’s still a solid burger.
• Turkey or chicken – Ground turkey (93/7) smashes and sears well, though the edges won’t get quite as lacy as beef; season a little more aggressively since turkey is leaner.
• Spicy sauce – Swap the yellow mustard for a tablespoon of sriracha and add a pinch of cayenne; it runs hotter than you expect.
• Dairy-free – Skip the American cheese and use a plant-based slice that melts; the sauce is already dairy-free as written.
• Extra acid – A light squeeze of yellow mustard directly on the bun in addition to the sauce adds another layer of sharpness if you like a tangier bite.
• Gluten-free – Use a gluten-free bun; everything else in the recipe is naturally gluten-free.

If you want to lean into the fast-food smash burger world even further, the Whataburger Patty Melt Copycat Recipe is worth a look next.

How To Make Sonic Double Smasher Burger

Step 1: Whisk the Sauce

Combine the 2 tbsp mayonnaise, 1 tbsp yellow mustard, 1 tbsp ketchup, 1 tsp pickle brine, 1/2 tsp garlic powder, and 1/2 tsp onion powder in a small bowl. Whisk until smooth. Set it aside at room temperature while you cook the burgers, so it stays loose and spreadable.

The sauce should look pale orange with visible yellow streaks. Give it one more stir before you spread it, since the mustard can settle slightly.

Step 2: Toast the Buns

Heat a skillet or griddle over medium heat. Place the buns cut-side down and press them lightly with your hand. Toast for about 2 minutes, until the cut surfaces are golden and slightly firm to the touch.

Pull them off the heat and set them aside. A toasted bun holds up to the sauce and juices without going soggy, which matters a lot with a saucy smash burger.

Step 3: Sear the Patties

Set a cast iron skillet or heavy steel pan over high heat and add the 1 tbsp vegetable oil. Let it heat for about 2 minutes until the oil is shimmering and just starting to smoke. While it heats, divide the 8 oz ground beef into 4 equal balls (2 oz each) without packing them tightly. Season each ball with the 1 tsp kosher salt and 1/2 tsp black pepper just before it hits the pan.

Working in batches of 2, place 2 beef balls in the pan and immediately press them flat with the back of a metal spatula or a burger press, pressing hard until each patty is about 4 to 5 inches wide and roughly 1/4 inch thick. Hold the pressure for 10 seconds. Cook undisturbed for 2 minutes, until the edges are visibly brown and lacy.

Don’t move the patties before those 2 minutes are up. The crust needs direct unbroken contact with the pan to form; if you lift them too soon, you’ll tear the sear and lose the whole point of smashing.

Step 4: Melt the Cheese

Flip each patty with a firm scrape of the spatula, getting underneath the crust cleanly. Immediately lay 1 slice of American cheese on each patty. Cook for 1 more minute on medium heat, until the cheese is fully melted and pooling over the edges of the meat.

Stack 2 patties together in the pan for about 15 seconds, cheese-sides touching, so the cheese between them fuses slightly. This is what gives you that pull-apart cheesy center when you bite through the double stack. Repeat with the second batch.

Step 5: Build and Garnish the Burgers

Spread the sauce evenly on both the top and bottom buns. On the bottom bun, layer 4 dill pickle chips, then the finely diced 1/4 white onion, then the double-stacked patty. Add 2 slices of tomato and a small handful of the 1 cup shredded iceberg lettuce. Press the top bun down gently, and serve immediately with a toothpick through the center to hold it tall.

Recipe Tips

• Use an 80/20 beef blend. Leaner beef dries out when smashed this thin. The fat renders into the pan and is what creates those crunchy, lacy edges.
• Cold beef smashes better. Keep the portioned balls in the fridge right up until you cook them. Cold fat holds together under pressure instead of squishing sideways.
• A metal spatula is non-negotiable. A silicone spatula won’t get under the crust cleanly. Use a thin, stiff metal spatula or a burger press with a flat base.
• Don’t overcrowd the pan. Two patties at a time maximum; too many patties drop the pan temperature and you end up steaming the beef instead of searing it.
• Leftover sauce keeps well. Store any extra sauce in a sealed jar in the fridge for up to 5 days. It works as a dipping sauce for fries or a spread for sandwiches.

Cook times by patty size:

How To Store

• Refrigerate – Store cooked patties separately from the buns and toppings in an airtight container for up to 3 days. The assembled burger does not keep well.
• Reheating – Re-sear the patties in a dry skillet over medium-high heat for about 1 minute per side to bring back some of the crust. The microwave works in a pinch but softens the edges.

What To Serve With Sonic Double Smasher Burger

Thin-cut shoestring fries are the natural pairing here, partly because their crunch echoes the crispy edges on the patties, and partly because they don’t compete for attention. A tangy coleslaw made with apple cider vinegar works well on the side because the acid cuts through the richness of the double beef stack and cheese. If you want something cold, a vanilla or chocolate shake ties the whole meal together the way it would at an actual Sonic, with the sweetness acting as a counterpoint to the salty, savory burger.

Frequently Asked Questions

Can I make these on a flat griddle instead of cast iron?

Yes, a flat griddle works just as well as cast iron as long as it gets hot enough to smoke slightly before the beef goes on. The key is surface contact, not the specific pan material.

Can I form the patty balls ahead of time?

Yes. You can portion the beef into balls, place them on a tray, cover with plastic wrap, and refrigerate for up to 24 hours before cooking.

What if my beef sticks to the spatula when I smash it?

Press a small square of parchment paper between the spatula and the beef ball before smashing. It peels off cleanly once the crust forms and you flip the patty.

Can I double the recipe for a group?

Easily. Keep finished patties warm on a wire rack set over a sheet pan in a 200°F (93°C) oven while you cook the remaining batches, then assemble all the burgers at once.

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Sonic Double Smasher Burger Recipe

Print Recipe Pin Recipe

Prep Time 10 minutes mins

Cook Time 15 minutes mins

Total Time 25 minutes mins

Servings: 2 servings

Ingredients Method Notes

Ingredients

  

• 8 oz (225g) 80/20 ground beef
• 2 plain burger buns
• 4 slices American cheese
• 1 tbsp vegetable oil
• 1 tsp kosher salt
• 1/2 tsp black pepper
• 2 tbsp mayonnaise
• 1 tbsp yellow mustard
• 1 tbsp ketchup
• 1 tsp pickle brine
• 1/2 tsp garlic powder
• 1/2 tsp onion powder
• 8 dill pickle chips
• 1/4 small white onion, finely diced
• 1 cup shredded iceberg lettuce
• 4 slices tomato

Method

 

1. Whisk together the 2 tbsp mayonnaise, 1 tbsp yellow mustard, 1 tbsp ketchup, 1 tsp pickle brine, 1/2 tsp garlic powder, and 1/2 tsp onion powder in a small bowl until smooth. Set aside.
2. Toast the buns cut-side down in a skillet over medium heat for about 2 minutes, until the cut surfaces are golden, then remove from heat.
3. Heat 1 tbsp vegetable oil in a cast iron skillet over high heat for 2 minutes until shimmering. Divide the 8 oz ground beef into 4 equal balls and season with 1 tsp kosher salt and 1/2 tsp black pepper. Working 2 at a time, place the beef balls in the pan and smash flat to about 1/4 inch thick. Cook undisturbed for 2 minutes.
4. Flip each patty and lay 1 slice of American cheese on top. Cook for 1 minute on medium heat until the cheese is melted, then stack 2 patties together for 15 seconds. Repeat with the second batch.
5. Spread the sauce on both bun halves. Layer 4 pickle chips, the diced onion, the double-stacked patty, 2 tomato slices, and a handful of shredded iceberg lettuce on the bottom bun. Press the top bun on and serve immediately.

Notes

These burgers are best eaten right off the pan. If you’re cooking for more than 2, hold finished stacked patties on a wire rack in a 200°F (93°C) oven for up to 10 minutes while you finish the rest, then assemble everything at once. The sauce doubles easily and tastes better after sitting for a few hours if you want to make it ahead.