I built this recipe around simple, high-impact staples to make a weeknight meal feel special. I used 1 lb ground beef, a teaspoon of truffle oil, thinly sliced yellow onions, Swiss or Gruyère, and soft buns to keep things familiar and satisfying.
The quick sauce is an easy mayonnaise-based aioli: mayo, lemon, salt, pepper, truffle oil, and grated garlic whisked until bright. It adds cream and lift without stealing the show.
I rely on a hot skillet to sear the patty, then melt the cheese fast so the interior stays juicy while the edge browns. Toasting the buns in butter gives a golden, slightly crisp finish that frames every bite.
My goal was a balanced flavor profile: savory beef, sweet onions, nutty cheese, and a whisper of truffle for depth. The method is short, the ingredients are pantry-friendly, and the result works for a casual night or a small gathering.
Key Takeaways
- Simple staples: 1 lb ground beef, truffle oil, mayo, lemon, and cheese deliver big flavor.
- Fast prep: Make the aioli and cook onions ahead to streamline skillet time.
- Technique matters: High heat sear and quick cheese melt keep the patty juicy.
- Balanced taste: Sweet onions and nutty cheese complement the beef without overpowering it.
- Weeknight-friendly: The recipe feels luxe but stays easy and repeatable.
Why this rich, savory smash burger belongs in my weeknight-to-dinner-party rotation
Weeknight cooking should feel effortless, so I focused on techniques that deliver deep flavor fast. I kept the core formula tight: 1 lb ground beef (85/15) for four patties, 1 tsp truffle oil in the sauce, and a simple seasoning of 1/2 tsp salt and 1/4 tsp black pepper on the meat.
What you’ll learn
Golden-brown onions cooked low and slow for 30–40 minutes add sweet depth while a very hot cast-iron skillet creates ultra-crispy edges in just a few minutes on medium-high heat.
I whisk the truffle aioli in a small bowl—mayo, minced garlic, lemon juice, and truffle oil—then season salt to taste. The sauce can rest up to five days, which keeps the stovetop run calm.
- I use 85/15 ground beef so thin patties stay juicy even when seared hard.
- Heat the skillet thoroughly, smash once, then season salt pepper as the meat hits the metal.
- Optional additions like mushrooms or baby arugula add umami or peppery lift, respectively.
For more topping ideas and a different flavor riff, see my take on a bacon and bleu variation at bacon bleu cheese burger.
Truffle-Swiss Caramelized Onion Smash Burger with Garlic Aioli Swirl
I keep the ingredient list tight so you can shop fast and cook even faster. Below is the full list for four: 1 lb ground beef; 1 tsp truffle oil; 1/2 tsp salt; 1/4 tsp ground black pepper; 1 large yellow onion, thinly sliced; 1–2 tablespoons oil; 1 tbsp butter; 4 slices Swiss cheese; 4 hamburger buns; 1/2 cup mayonnaise; 2 cloves garlic, minced; 1 tsp lemon juice; additional salt and pepper to taste.
Truffle aioli essentials
I whisked mayo, minced garlic, lemon juice, and a measured drizzle of truffle oil, then adjusted to salt pepper taste. A little truffle oil goes a long way; the sauce keeps for several days in the fridge.
Caramelized onion setup
Heat 1–2 tablespoons oil in a large skillet set over medium heat. Add the thinly sliced onions with a pinch salt and cook, stirring often, 30–40 minutes until they are deep and sweet.
Beef, cheese, and buns
I used 85/15 ground beef for juicy patties and topped each with a slice cheese of Swiss or Gruyère. I butter the bun halves and toast them in the skillet until golden.
Smart swaps and notes
- White cheddar works if Swiss isn’t on hand.
- Skip truffle oil for a bright lemon-and-mustard riff in the sauce.
- Gluten-free buns or a handful of sautéed mushrooms are easy upgrades.
Step-by-step: from golden onions to crispy-edged patties and a glossy aioli swirl
I start by tackling the onions so they can slowly turn sweet while I prep everything else. Heat 1–2 tablespoons oil in a large skillet over medium heat, add the thinly sliced onions with a pinch salt, and stir often for 30–40 minutes until deeply golden brown. Reduce heat if they brown too fast, then set aside.
Make the truffle aioli
In a small bowl I whisk 1/2 cup mayonnaise, 2 cloves finely grated garlic, 1 tsp lemon juice, and 1 tsp truffle oil until glossy. I season to taste with salt and ground black pepper, then set aside so the flavors meld.
Form and cook the patties
I portion the ground beef into loose 2.5–3 oz balls, keep the cast-iron skillet set over medium-high heat until very hot, then smash each ball for 2–3 minutes to build crisp, frilly edges. I season immediately with salt and a touch of ground black pepper, flip, lay on a slice cheese, and cook 1–2 minutes more to melt.
Toast, assemble, serve
I lightly butter the bun cut sides and toast them in the same skillet until golden. To assemble: swipe aioli on the bottom bun, add one or two patties, pile on the caramelized onions, add arugula or a mushroom addition if desired, then top and serve.
| Step | Time (minutes) | Purpose |
|---|---|---|
| Onions in oil large skillet | 30–40 | Develop deep sweetness and set aside for topping |
| Whisk truffle aioli (small bowl) | 5 | Make glossy sauce to finish the build |
| Smash patties on very hot skillet | 2–3 per side | Create lacy crust and melt cheese |
| Toast buns in butter | 1–2 | Add structure and golden finish |
Tip: I keep extra sauce set aside at the table and adjust seasoning—season salt pepper—just before serving to ensure each bite is balanced. For a savory twist, I link to a mushroom variation for more ideas and extra inspiration.
- Set aside cooked onions so they stay warm but not overcooked.
- Keep the skillet hot for crust, reduce heat when toasting buns or holding patties.
- If you want a mushroom add, see the mushroom variation for tips: mushroom variation.
- For a different take and plating ideas, check extra inspiration: extra inspiration.
Conclusion
With smart ratios and a little heat control, any weeknight can become memorable dinner.
I kept the staples simple: 1 lb ground beef, 1 tsp truffle oil, 1 large yellow onion, Swiss, butter, buns, 1/2 cup mayo, 2 cloves garlic, and 1 tsp lemon juice. These measures let me hit steakhouse-level flavor with minimal shopping.
The truffle aioli can rest up to five days and the onions reheat gently. A very hot cast-iron skillet and a light film of oil produced the crisp crust in just minutes per side.
I used salt pepper as my base seasoning and finished to salt pepper taste so the lemon and truffle notes stayed bright. Try a spoon of extra sauce, a thin layer of arugula, or a swap to Gruyère or sautéed mushrooms for small variations.
Make this soon—the components store well, assembly takes minutes, and the repeatable results keep this recipe in my rotation of quick, impressive recipes. For a related riff, see the mushroom variation at mushroom variation.
FAQ
How do I prevent the onions from burning while I caramelize them?
I cook sliced yellow onions over medium heat in a large skillet with a bit of oil and a pinch of salt, stirring often. If they start to stick or brown too fast, I lower the heat and add a splash of water or a touch of butter. Patience is key — low and slow yields deep, golden flavor without burning.
What grind and fat ratio of beef should I use for the crispiest edges?
I use 85/15 ground beef for a good balance of juiciness and fat needed to form thin, crispy-edged patties when smashed on a very hot cast-iron skillet. The higher fat renders and helps create the Maillard crust I want.
How do I make the truffle aioli so it’s bright and not overly oily?
I whisk together mayonnaise, minced garlic, lemon juice, and a small amount of black truffle oil in a small bowl. The lemon juice brightens the mayo and cuts through richness; I add truffle oil sparingly and season with salt and pepper to taste so the aroma is balanced, not overpowering.
Can I skip the truffle oil or substitute it if I don’t have any?
Yes. I sometimes skip truffle oil and add a teaspoon of mushroom paste or finely minced sautéed mushrooms for umami, or use a few drops of truffle-infused salt instead. These swaps give a similar earthy note without the intense perfume of straight truffle oil.
How long does it take to caramelize onions properly?
I plan on 25–40 minutes to get deeply golden-brown onions, depending on pan size and heat. Stir regularly and adjust heat so they slowly soften and darken; rushing at high heat risks bitter, burnt edges instead of sweet complexity.
What’s the best way to toast buns for this sandwich?
I butter the cut sides lightly and toast them in the same skillet over medium heat until golden. Using the pan after cooking the patties adds flavor from the fond and keeps the buns crisp where they meet the patties.
Should I season the beef before smashing, and when do I add salt and pepper?
I form loosely packed beef balls and place them on the hot skillet, then immediately season the top with salt and ground black pepper before smashing. Seasoning before contact helps build the crust; I add a final pinch after flipping if needed.
Do I need to rest the patties after cooking?
For thin smash patties I don’t rest them long because they cool quickly. I typically add the cheese, let it melt briefly, then assemble right away so the bun and aioli capture the juices while the patty is still hot.
Can I add mushrooms to the recipe, and how should I prepare them?
I often add sliced mushrooms as an optional mix-in. I sauté them first in butter or oil until golden and set them aside with the onions. If you want an earthy boost instead of truffle, mixing mushrooms into the aioli or layering them on the patty works well.
What cheese works best if I don’t have Swiss or Gruyère?
I recommend white cheddar or provolone as smart swaps; they melt nicely and complement the savory components. Choose a slice that melts quickly so it blankets the patty without overpowering the truffle notes.
My Truffle-Swiss Caramelized Onion Smash Burger with Garlic Aioli Swirl
- Total Time: 60
- Yield: 4 1x
Description
Gourmet truffle smash burger with caramelized onions, Swiss cheese, and homemade garlic aioli. Crafted for discerning home chefs seeking restaurant-quality results with weeknight-friendly techniques.
Ingredients
1 lb ground beef (85/15)
1 tsp truffle oil
1/2 tsp salt
1/4 tsp ground black pepper
1 large yellow onion, thinly sliced
1–2 tablespoons oil
1 tbsp butter
4 slices Swiss cheese
4 hamburger buns
1/2 cup mayonnaise
2 cloves garlic, minced
1 tsp lemon juice
Additional salt and pepper to taste
Instructions
1. Heat 1-2 tablespoons oil in large skillet over medium heat. Add sliced onions with pinch of salt and cook, stirring often, for 30-40 minutes until deeply golden brown.
2. Whisk together mayonnaise, minced garlic, lemon juice, and truffle oil in small bowl. Season with salt and pepper to taste. Set aside.
3. Portion ground beef into loose 2.5-3 oz balls. Heat cast-iron skillet over medium-high heat until very hot.
4. Smash each beef ball in hot skillet for 2-3 minutes to build crisp edges. Season immediately with salt and pepper. Flip, add cheese slice, cook 1-2 minutes more to melt.
5. Lightly butter cut sides of buns and toast in same skillet until golden.
6. Assemble burgers: spread aioli on bottom bun, add patties, pile caramelized onions, top with remaining bun half and serve immediately.
Notes
Use 85/15 ground beef for optimal juiciness and crispy edges when smashed.
Caramelized onions can be made ahead and reheated gently before serving.
Truffle aioli keeps in refrigerator up to 5 days – make ahead for quick assembly.
Swiss or Gruyère cheese both work perfectly – choose your preference.
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- Prep Time: 15
- Cook Time: 45
- Category: gourmet-appetizers
- Method: pan-seared
- Cuisine: American-gourmet
Nutrition
- Serving Size: 1
- Calories: 650
- Sugar: 8g
- Sodium: 890mg
- Fat: 42g
- Saturated Fat: 18g
- Unsaturated Fat: 20g
- Trans Fat: 0g
- Carbohydrates: 32g
- Fiber: 3g
- Protein: 35g
- Cholesterol: 95mg