Keto beef burger with avocado mayo (lettuce bun)
Juicy low‑carb beef burgers, crispy bacon and melted mature cheddar, served in butter lettuce with creamy avocado mayo.
This is the keto burger that lets you eat a proper burger without the bun guilt. Big on flavour, rich in healthy fats and still low in carbs — ideal for a midweek supper or weekend treat.
You make a quick avocado mayo instead of sugary ketchup, crisp the bacon and melt mature cheddar on top of juicy beef patties. Serve in butter lettuce leaves for the familiar burger experience without the carbs.
Ingredients
- 500 g beef mince
- 1 egg — large
- 5 ml sea salt
- 5 ml black pepper — freshly ground
- 5 ml garlic powder
- 5 ml onion powder
- 5 ml smoked paprika
- 120 g mature cheddar — sliced into 8 thin slices
- 8 butter lettuce leaves — large outer leaves for buns
- 1 ripe avocado — medium
- 100 g mayonnaise
- 15 ml lemon juice — about 1 tbsp
- 15 ml olive oil — for frying
- 8 streaky bacon — rashers
- 1 tomato — medium, sliced
- 1 red onion — small, thinly sliced
- 4 gherkin — small, sliced
Equipment
- meat thermometer
Instructions
Make the avocado mayo: scoop the ripe avocado into a bowl and mash with a fork until mostly smooth. Stir in the mayonnaise and lemon juice, season with a pinch of sea salt and a grind of black pepper. Chill in the fridge while you prepare the patties.
Mix the burger mince: put the beef mince in a large bowl, add the egg, sea salt, black pepper, garlic powder, onion powder and smoked paprika. Gently combine with your hands or a fork until the seasoning is evenly distributed — do not overwork the meat or the patties will be dense.
Shape into 4 even patties (about 125 g each). Make a shallow thumb indentation in the middle of each patty to help them keep a flat shape while cooking. Place on a plate, cover loosely and chill for 15 minutes to firm up — this helps prevent excessive shrinkage when frying.
While the patties chill, cook the bacon: heat a frying pan over medium heat with 5 ml olive oil and fry the streaky bacon for 6–8 minutes, turning occasionally, until crisp. Transfer to a plate lined with kitchen paper to drain.
Fry the patties: increase the heat to medium‑high and add the remaining 10 ml olive oil to the pan. Fry the chilled patties for 4 minutes on the first side without moving them, flip and cook for a further 3–4 minutes for medium (adjust time to your preference). In the last minute, top each patty with two slices of mature cheddar and cover the pan briefly so the cheese melts.
Rest the cooked patties on a clean plate for 5 minutes. Resting lets the juices redistribute and avoids them spilling out when you assemble the burgers.
Assemble the burgers: use two butter lettuce leaves as each 'bun'. Spread a tablespoon of avocado mayo on the base leaf, add a cheese‑topped patty, two rashers of bacon, a slice of tomato, a few rings of red onion and slices of gherkin. Finish with more avocado mayo and the top lettuce leaf. Serve immediately.
Tips
- Don’t overwork the mince when mixing — that’s the number one cause of tough burgers.
- Chill the patties for at least 15 minutes; it helps them hold shape and reduces shrinkage.
- Use a meat thermometer to check doneness: minced beef should reach 70°C for safety.
- Make the avocado mayo ahead and keep chilled up to 24 hours; add lemon juice just before serving if it looks a little darkened.
- Leftover patties keep well in the fridge for 2 days and reheat gently in a low oven (150°C fan/170°C conventional) to avoid drying out.
Substitutions
beef mince → lamb mince, same weight
Stays closemayonnaise → full‑fat Greek yoghurt, same weight (will be slightly tangier and add a few more carbs)
Noticeably differentbutter lettuce leaves → large cos lettuce leaves or iceberg leaves, same quantity
Stays closestreaky bacon → pancetta rashers, same quantity
Stays close
Nutrition
Per serving · estimated
- 880
- Calories
- 48 g
- Protein
- 7 g
- Carbs
- 73 g
- Fat
- 3 g
- Fibre
- 3 g
- Sugar
- 900 mg
- Sodium
FAQ
Can I make these burgers ahead of time?
You can form the patties and keep them covered in the fridge for up to 24 hours. Cooked patties will keep 2 days in the fridge — reheat gently to avoid drying out.
How do I keep the patties from shrinking?
Chill the shaped patties for at least 15 minutes before frying and make a shallow indentation in the centre of each to counteract doming.
Can I freeze the burgers?
Freeze uncooked patties individually on a tray, then transfer to a bag for up to 3 months. Thaw overnight in the fridge before cooking.
What if I don’t have a meat thermometer?
Cut into one patty to check: juices should run clear and there should be no pink in the centre for safety with minced beef, though many prefer just‑done for juiciness.
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