Smash Burgers with Caramelized Onions & Chipotle-Lime Crema
6 colorSTHE WHY BEHIND THIS RECIPE
I made these and sent them out to many of you to test—and the verdict was unanimous: they’re ready for prime time! They taste better than they photograph.
In my opinion, a great burger needs salt and fat (from the beef of course), but also acid (hello, lime crema), heat (from the chipotle), and a touch of sweetness—which you get from the caramelized onions. This is my quick-and-dirty 15-minute caramelized onion hack. You might recognize it from my Greek Beef Frittata recipe. Professional chefs might disagree, but for busy home cooks, it more than gets the job done.
I also tested a few burger bun recipes, and to be honest….these are best lettuce-wrapped. I know, I know - but you can really taste the other flavors so much more without the bun! That said, if you're a bun person, go for it! It’s a great excuse to swing by a local bakery for some sourdough or your buns of choice. I haven’t found a gluten-free bun brand I love—Base Culture and Against the Grain are fine, but not amazing. If you have one you swear by, please send it my way!!
Yields: 4 burgers
Total time: 30 minutes
Prep time: 20 minutes
Cook time: 10 minutes
WHAT YOU NEED
TOOLS
INGREDIENTS
For the Smash Burgers
1 lb grass-fed ground beef (I use Force of Nature Ancestral blend)
1 tsp kosher salt
fresh ground black pepper
4 slices grass-fed cheddar
For the Caramelized Onions
1 medium yellow onion, thinly sliced
1 tbsp butter and 1 tbsp olive oil (this is the best combo for carmelizing)
Pinch of salt
For the Wraps + Toppings
8 large butter lettuce or romaine leaves (for wrapping) - or your favorite burger bun!
8 fermented pickle slices
4-6 tomato slices (optional)
For the Sauces
Chipotle-Lime Crema:
1/3 cup full-fat greek yogurt
1 tsp chipotle powder (or 1 tbsp adobo sauce from canned chipotles)
Juice of 1 lime
Pinch of salt
Primal Kitchen ketchup and pickles for serving!
HOW TO DO IT
1.Caramelize the onions: - here’s how to caramelize onions in 10-15 minutes 👇🏼
Preheat the pan – Heat a large stainless steel or cast iron skillet over medium-high heat. Add 1 tbsp butter and 1 tbsp olive oil (the combo prevents burning while adding flavor!).
Add the onions & salt – Toss the sliced onions into the pan and sprinkle with salt (this helps draw out moisture).
Start with high heat for 5 minutes – Let the onions cook over medium-high heat, stirring every 30-60 seconds. They will start to release water and soften.
Deglaze as needed – As brown bits develop on the pan, add 1 tablespoon of water and scrape them up with a wooden spoon. Repeat as necessary to prevent burning while encouraging caramelization.
Add a small pinch of baking soda (about 1/8 tsp). You want to do this after the onions have softened and started releasing moisture but before the deep browning begins. Baking soda weakens the onion’s cell structure, releasing more sugars and speeding up browning. I’ve done this step and skipped this step, and it worked a little better with the baking soda but it was not imperative.
Timing of baking soda matters: If added too early, baking soda can make the onions break down too much, turning them mushy. If added too late, it won’t have as much time to accelerate browning effectively.
Reduce heat to medium & continue cooking – After about 5 minutes, lower the heat to medium and continue cooking for another 7-10 minutes, stirring every 30-45 seconds and deglazing with water when needed.
Remove from skillet and set aside!!
2.Make the chipotle-lime crema
In a small bowl, mix 1/3 cup greek yogurt, 1 tsp chipotle powder (or 1 tbsp adobo sauce from canned chipotles), juice from 1 lime, and a pinch of salt until smooth. Chill until ready to use.
3.Prep the lettuce wraps
Wash and dry lettuce leaves. Set aside in stacks of 2 for sturdier wraps.
4.Form the burger balls
Divide ground beef into 4 loose balls (about 3 oz each). Don’t pack tightly. Season the tops with salt and pepper. Don’t salt the beef until just before smashing—salting too early can make it tough.
5.Smash & sear the burgers
Heat a cast iron skillet or griddle until very hot. Add in 1 tbsp tallow or avocado oil. Place 2 balls in the pan, then immediately smash them flat with burger smasher or spatula. Cook undisturbed for 1.5–2 minutes until a deep brown crust forms. Flip, top with cheddar, and cook 30–60 seconds more. Repeat with remaining burgers.
6.AssemblE AND SERVE
On each lettuce base, layer:
One or two burger patties with melted cheese
A spoonful of caramelized onions
Pickle slices
Tomato (if using)
A dollop of of chipotle-lime crema
Fold like a taco or bundle with parchment if needed. You can also stick a toothpick down the center to keep them all intact! Serve with crispy sweet potato wedges, roasted carrots, watermelon-feta-mint salad, or whatever your favorite summer side is!
SWAPS, TIPS & TRICKS
SWAPS:Cheddar: Swap with any cheese you fancy or omit entirely and add creamy avocado.
Lettuce Wraps:
Sub Siete almond flour tortillas, coconut wraps, or simple romaine hearts for a more taco-style wrap.
Gluten-free bun: Use Base Culture or Against the Grain, or try to find one at a local bakery!
Chipotle powder: Substitute with 1/2 tsp smoked paprika and 1/2 tsp chili powder (more to taste)
TIPS:Smashing the burgers:
Don’t salt the beef until just before smashing—salting too early can make it tough.
Preheat the pan well—the crust only forms with a screaming hot surface.
Burger size: Form loose meatballs—not tight patties—before smashing to preserve texture.
Caramelized onions:
Can be made ahead of time and reheated!
Don’t skip the deglazing! Water, broth, or even a splash of balsamic helps develop flavor.
Burger assembly:
Double up on lettuce leaves crosswise, not stacked—this gives better structure and less tearing.
You can also wrap in parchment or foil for easier eating, especially for kids or guests!
Nutritional Info
Per burger with all the fixings mentioned here!
Calories: 543
Carbohydrates: 15g
Fiber: 5g
Net carbs: 10g
Protein: 33g
Fat: 40g
Sodium: 1521mg
Sugar: 5g
