Ingredients

• 1 large sweet white onion
• sliced into 1cm/½in rings
• 1 litre/1¾ pints buttermilk
• 175g/6oz plain flour
• sifted
• 50g/2oz polenta
• 1½ tbsp sea salt
• freshly ground black pepper
• 1 tbsp chilli powder
• vegetable oil
• for deep frying
• balsamic vinegar
• to serve
• 600g/1lb 5oz steak mince
• salt and freshly ground black pepper
• 50ml/2fl oz olive oil
• 4 x onion focaccia buns
• sliced
• griddled until slightly charred
• ready-made mayonnaise
• to taste
• 1 large beefsteak tomato
• sliced
• 2 large gherkins
• sliced
• handful rocket leaves

Directions

• For the onion rings
• heat the vegetable oil in a deep
• heavy-bottomed pan until a bread crumb sizzles and turns brown when dropped into it. (CAUTION: hot oil can be dangerous. Do not leave unattended.)
• Place the separated rings of sliced onion into a large bowl with the buttermilk to soak for 30 minutes
• stirring occasionally.
• Place the flour
• polenta
• salt
• freshly ground black pepper and chilli powder into a clean bowl and mix well. Transfer the mixture to a large plate.
• Take individual onion rings from the buttermilk
• making sure there's lots of buttermilk clinging to the onion.
• Dredge each ring in the flour and polenta mixture and set aside
• taking care not to shake off any excess flour and polenta coating.
• Carefully add the coated rings to the hot oil in batches of six and fry
• stirring occasionally
• for 3-4 minutes
• or until crisp and golden. (The rings may sink to the bottom at first
• but will then float to the top as they cook.)
• Carefully remove the rings with a slotted spoon and drain on kitchen paper. Repeat the deep-frying process until all of the onion rings are cooked.
• For the burger
• place the mince into a bowl and season well with salt and freshly ground black pepper.
• Divide the mince into four and mould each piece into a patty shape.
• Brush each patty with the olive oil and place onto a hot griddle pan. Cook for four minutes on each side
• or until completely cooked through.
• Place a burger inside each focaccia bun. Spoon over mayonnaise
• to taste
• and garnish with lettuce
• tomato and gherkins.
• To serve
• place the onion rings into a large bowl and sprinkle with salt. Place a small bowl of balsamic vinegar alongside to dip into.
• Place the burgers and buns onto plates and serve with the onion rings.