There’s nothing like a smash burger with juicy patties and perfectly caramelized onions for a truly satisfying meal.
This method creates crispy edges while locking in moisture, and the onions add sweetness that complements every bite.
Ingredients for Smash Burger Recipe with Onions
Crafting perfect smash burgers requires quality beef, caramelized onions, and classic condiments. Nothing extravagant, just essentials.
| Ingredient | Amount | Notes |
|---|---|---|
| Ground Beef Chuck 🥩 | 1 ½ lb | 80/20 fat ratio for juiciness |
| Yellow Onions 🧅 | 2 whole | Thinly sliced for caramelizing |
| Kosher Salt 🧂 | 1 ½ tsp | Diamond Crystal preferred for even seasoning |
| Freshly Ground Black Pepper 🌶️ | 1 tsp | Coarse grind for texture |
| American Cheese Slices 🧀 | 4 slices | Or cheddar for sharper flavor |
| Potato Hamburger Buns 🍞 | 4 whole | Soft, slightly sweet variety |
| Unsalted Butter 🧈 | 2 tbsp | For toasting buns and cooking |
| Neutral Oil 🫒 | 2 tbsp | High smoke point like avocado or vegetable |
| Garlic Powder 🧄 | ½ tsp | For seasoning onions |
| Worcestershire Sauce 💧 | 1 tsp | For umami depth in onions |
| Mayonnaise 🥛 | ¼ cup | For spreading on buns |
| Dijon Mustard 🟡 | 2 tbsp | For tangy contrast |
| Bread and Butter Pickles 🥒 | ½ cup | Sliced, for topping |
| Lettuce Leaves 🥬 | 4 whole | Iceberg or butter lettuce for crunch |
| Tomato Slices 🍅 | 4 slices | Ripe but firm for texture |
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The beef is non-negotiable here. 80/20 ground chuck from a trusted butcher or Whole Foods ensures the right fat content for juicy patties with crispy edges. Avoid pre-formed patties—they won’t smash properly. For the onions, yellow onions caramelize beautifully and are readily available. Look for firm bulbs with papery skins at any major supermarket.
No American cheese? Sharp cheddar or pepper jack work well, though they won’t melt quite as smoothly. The buns can be brioche if you prefer a richer flavor, but potato buns maintain structural integrity under the juices. For a deeper onion flavor, add a pinch of sugar while caramelizing. If avoiding Worcestershire, substitute coconut aminos for similar umami depth.
Cooked patties and caramelized onions can be held in a 200°F oven for up to 30 minutes while assembling. Store raw beef in the fridge for up to 2 days or freeze for 3 months. Assemble burgers just before serving to prevent sogginess.
Why You’ll Love This Recipe
- 20-Minute Meal: I can go from raw beef to juicy, cheesy burgers faster than the oven preheats.
- Caramelized Crunch: The smashing technique turns those yellow onions into sweet, crispy bits that cling to every bite.
- Crowd Pleaser: Honestly, even my pickiest nephew will devour two of these with extra cheese.
Step-by-Step Instructions for Smash Burgers With Onions
Master the technique that creates irresistibly crispy edges and perfectly juicy centers with caramelized onion topping.
Step 1: Caramelize the Yellow Onions
Heat 2 tbsp neutral oil in a large skillet over medium-low heat. Add the 2 whole yellow onions, thinly sliced, and cook for 5 minutes until they begin to soften and become translucent, stirring occasionally.
Sprinkle the onions with 0.5 tsp garlic powder and 1 tsp Worcestershire sauce. Season with a pinch of 1.5 tsp kosher salt and 1 tsp freshly ground black pepper. Continue cooking for 15-20 minutes, stirring every 2-3 minutes, until the onions are deep golden brown and sweet with a rich, jammy consistency. Lower heat if they begin to darken too quickly.
Step 2: Form and Smash the Patties
Divide the 1.5 lb ground beef chuck into 4 equal portions (about 6 oz each) and loosely form them into balls. Don’t overwork the meat—this keeps the patties tender. Heat a cast-iron skillet or griddle over medium-high heat until very hot.
Place one ball in the skillet and immediately press down firmly with a metal spatula until the patty is thin (about ¼-inch thick). Press for 10 seconds to ensure maximum contact with the pan. Repeat with the remaining balls, working in batches if necessary. Season each patty with a pinch of the kosher salt and freshly ground black pepper.
Step 3: Cook the Burgers and Add Cheese
Cook the patties undisturbed for 2-3 minutes until the edges are deep brown and crispy and the tops are beginning to look cooked. Use the spatula to scrape the patties off the pan—this ensures all the crispy bits stay intact.
Flip each patty and immediately top with a slice of American cheese slices. Cook for an additional 1-2 minutes until the cheese is melted and the patties are cooked through. Transfer the patties to a plate and tent loosely with foil to keep warm.
Step 4: Toast the Buns and Assemble
Spread 2 tbsp unsalted butter on the cut sides of the 4 whole potato hamburger buns. Toast in the same skillet over medium heat for 1-2 minutes until golden brown and lightly crisp.
Spread the bottom buns with 0.25 cup mayonnaise and the top buns with 2 tbsp Dijon mustard. Place a cheesy patty on each bottom bun, then top with the caramelized onions, 4 whole lettuce leaves, 4 slices tomato slices, and 0.5 cup bread and butter pickles. Cap with the top buns and serve immediately while hot.
Pro Tips For Making Smash Burger Recipe With Onions
- Chill the Beef: Pop your ground chuck in the fridge for 30 minutes before forming into balls—keeps the fat from rendering too fast when you smash it. I learned this the hard way after my first few burgers turned greasy and flat.
- Smash Hard and Fast: Use a stiff metal spatula and press down with real force for 10-15 seconds—this is the only way to get that crispy, caramelized crust on the beef.
- Caramelize the Onions: Start cooking your yellow onions low and slow in a separate pan while you prep the beef—they need a good 20-25 minutes to turn sweet and jammy, and doing this first saves you from rushing later.
- Cheese Last: Add the American cheese slices only after flipping the burger—putting it on too early melts it into the pan instead of onto the patty. Sounds obvious, but I’ve ruined a few this way.
Flavor Customization for This Dish
Cheese Variations
Swap American cheese for sharp cheddar if you prefer a bolder, tangier flavor that stands up to the sweet onions. For a smoky twist, pepper jack adds heat, while Swiss cheese offers a nutty, melt-in-your-mouth experience. 🧀
Spicy Kick
Add ½ tsp cayenne pepper to the beef before smashing for a subtle heat. For more intensity, mix 1 tbsp sriracha into the mayonnaise for a spicy mayo spread. Top with jalapeño slices if you want extra fire.
Umami Boost
Enhance the onions with 1 tbsp soy sauce or 1 tsp fish sauce while caramelizing for deeper savory notes. A sprinkle of grated Parmesan on the patties before adding the main cheese layer adds a salty, nutty dimension.
Sweet and Tangy
Replace Dijon mustard with honey mustard for a sweeter contrast. For a Southern touch, add 2 tbsp bourbon-glazed bacon to the burger. The sugar in the glaze pairs beautifully with the caramelized onions. 💛
Herb Infusion
Mix 1 tbsp chopped fresh rosemary or thyme into the beef for an aromatic lift. Alternatively, add 1 tsp smoked paprika to the patties for a subtle, earthy flavor that complements the onions.
Crunchy Texture
Add ¼ cup crispy fried shallots on top of the onions for an extra layer of crunch. Or, swap the pickles for pickled jalapeños to add both heat and texture to each bite.
Nutrition Facts
Frequently Asked Questions
Why do you smash the patties thin?
Smashing creates maximum surface contact with the hot pan, forming a crispy crust while keeping the inside juicy. The thin shape also ensures quick, even cooking.
How do I keep the burgers from steaming?
Cook in batches and avoid crowding the pan. This allows heat to circulate properly, preventing the patties from steaming instead of searing. Use a cast-iron skillet for best results.
Can I use pre-sliced onions?
Yes, but fresh thinly sliced onions caramelize more evenly. If using pre-sliced, pat them dry first to remove excess moisture. Cook on medium-low heat for 20-25 minutes.
What’s the best way to melt the cheese?
Place the cheese on the patty immediately after flipping. Cover the pan for 30 seconds to trap heat and melt the cheese faster without overcooking the beef.
Trained in classic French technique but raised on slow-cooked ribs and spicy rubs, she blends culinary skill with smoke and soul.
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