Don’t skimp on the quality of your beef and you’ll have a burger worth serving with these homemade rosemary-salted chips and mustard mayo. Add a slice of cheese for extra decadence if you like too.
For the burgers, thinly slice the red onion and place in a bowl with the red wine vinegar and sugar. Set aside to pickle while you make the burger.
Season the mince to your taste with sea salt and pepper and shape into 150g/5½oz patties using your hands. Set aside.
For the mustard mayonnaise, separate the egg yolks into a bowl and gradually stir in the oil until creamy in consistency, whisking all the time.
Stir in the wholegrain mustard and vinegar, season, to taste and refrigerate.
For the chips, heat the vegetable oil in a deep fat fryer to 130C/275F (CAUTION: hot oil can be dangerous. Do not leave unattended.)
Deep fry the rosemary for 30 seconds, remove with a slotted spoon and drain on a plate lined with kitchen paper. Chop the rosemary finely, mix it with the sea salt and leave to one side.
Peel and cut the potatoes into chunky chips, place on a tray and steam for 15 minutes.
Deep fry the chips for 3-4 minutes at 130C/275F. Remove with a slotted spoon and drain on a plate lined with kitchen paper.
Increase the heat of the oil to 180C/350F and fry again until crisp. Remove with a slotted spoon, drain on kitchen paper and then toss the chips in the chopped rosemary and salt, to taste.
Preheat a grill to hot. Cook the burgers for 4-5 minutes each side under the grill.
Layer the burger on the roll with gherkin, bacon and reserved onion. Serve with the hot rosemary-salted chips and mustard mayonnaise.
If it's a priority that this recipe is dairy free, check the label on the bread rolls as some contain dairy products.
