The Ketovore

Keto Smash Burgers with Caramelized Onion and Bacon Jam

Keto Smash Burgers with Caramelized Onion and Bacon Jam

Forget everything you know about thick, juicy pub burgers. The smash burger is a different beast entirely—and once you taste that lacey, caramelized crust that only comes from pressing beef against a screaming-hot griddle, there is no going back.

These keto smash burgers take the classic diner-style patty and crown it with a savory-sweet bacon jam that will ruin you for regular condiments forever. Imagine crispy bacon slow-cooked with caramelized onions until it becomes this sticky, umami-rich spread that melts into every crevice of the burger. It is obscenely good.

Wrapped in crisp butter lettuce (or your favorite keto bun), these clock in at just 3 grams of net carbs. This is fast food done right—made at home in about 20 minutes, no drive-thru required.

Why This Recipe Works

  • Maximum Maillard: Smashing creates more surface area for that addictive crispy crust.
  • Fast and forgiving: Two minutes per side. Even overcooked, the thin patty stays juicy thanks to the fat content.
  • Bacon jam is a game-changer: Sweet, savory, smoky—it transforms a simple burger into something special.
  • Totally customizable: Add cheese, pickles, jalapeños, whatever you are craving.
Smash burger ingredients on marble counter
Smash burger mise en place—ready to sizzle

Ingredients

For the Smash Burgers

  • 1 lb ground beef (80/20 for best flavor)
  • 1 tsp salt
  • 1/2 tsp black pepper
  • 4 slices sharp cheddar (optional)
  • Butter or beef tallow for the griddle

For the Bacon Jam

  • 8 oz bacon, chopped
  • 1 medium onion, thinly sliced
  • 2 cloves garlic, minced
  • 2 tbsp apple cider vinegar
  • 2 tbsp brown sugar substitute (allulose or Swerve)
  • 1/4 cup water
  • Pinch of cayenne (optional)

To Serve

  • Butter lettuce leaves or keto buns
  • Sliced pickles
  • Yellow mustard
  • Sugar-free ketchup

Instructions

Make the Bacon Jam

  1. Cook chopped bacon in a skillet over medium heat until crispy, about 8 minutes. Remove bacon, leave the fat.
  2. Add sliced onions to the bacon fat. Cook low and slow for 15-20 minutes until deeply caramelized.
  3. Add garlic, cook 1 minute. Add vinegar, sweetener, water, and cayenne.
  4. Return bacon to pan. Simmer until thick and jammy, about 10 minutes.
  5. Let cool slightly. Can be made ahead and refrigerated for up to a week.

Make the Burgers

  1. Divide ground beef into 4 equal balls (about 4 oz each). Do not season yet.
  2. Heat a cast iron skillet or griddle over high heat. Add a small amount of butter or tallow.
  3. Place a ball on the hot surface. Immediately smash flat with a sturdy spatula or burger press. Season with salt and pepper.
  4. Cook 2 minutes until edges are crispy and brown. Flip, add cheese if using, cook 1 more minute.
  5. Repeat with remaining patties.

Assemble

  1. Place patties in lettuce cups. Top with a generous spoonful of bacon jam.
  2. Add pickles, mustard, or your favorite toppings. Serve immediately.

Nutrition (per burger with jam)

  • Calories: 480
  • Fat: 38g
  • Protein: 28g
  • Net Carbs: 3g

Tips

  • Do not touch it: Once you smash, leave it alone until it is time to flip. Let the crust develop.
  • Hot, hot, hot: The pan should be smoking. This is not gentle cooking.
  • Double up: Stack two patties for the ultimate double smash.