• Preheat your oven to 240°C/220°C fan/gas mark 9.
• Chop the potatoes lengthways into 1cm slices, then into 1cm wide chips (no need to peel).
• Pop the chips onto a lined baking tray. Drizzle with oil, season with salt and pepper then toss to coat. Spread out in a single layer.
• Cook on the top shelf until golden, 25-30 mins. Turn halfway through. 

TIP: Use two baking trays if necessary.

• Quarter the apple and remove the core and seeds.
• Coarsely grate one-quarter of the apple and set aside.
• Cut the remaining apple lengthways into thin slices.

• Peel the onion then slice into thin rings. 
• In a large bowl, mix together the balsamic vinegar, salt, pepper and a drizzle of oil.
• Add the onion rings to the bowl and toss to coat.
• Leave to marinate until serving.

TIP: The thinner you slice the onion the less bite it will have.

• In a large bowl, combine the beef mince with the grated apple and the breadcrumbs. IMPORTANT: Wash hands and equipment after handling raw mince. 
• Season with salt and pepper and mix everything together with your hands. 
• Roll into even-sized balls, then shape into 1cm thick burgers, 1 per person.

• Place a pan over medium-high heat with a drizzle of oil.
• Once hot, fry the burgers until browned on the outside and cooked through, 12-14 mins.
• Carefully turn every 3-4 mins, adjusting the heat if needed. IMPORTANT: Burgers are cooked when no longer pink in the middle.
• Once cooked, remove pan from heat and divide the cheese between burgers. Cover and set aside until the cheese is melted, 3-4 mins.
• Pop the buns into the oven to warm, 2-3 mins.

• To assemble the burgers, spread a spoonful of mayo over each base bun. 
• Top with beef burger, apple slices and marinated onion. Close with the top bun. 
• Serve with chips and any remaining apple slices alongside.