Preheat your oven to 220°C/200°C fan/gas mark 7.

Chop the potatoes into 2cm wide wedges (no need to peel). Halve, peel and slice the red onion as thinly as you can. Pick the rosemary leaves from their stalks and roughly chop (discard the stalks).

Pop the wedges onto a large baking tray. Drizzle with oil and scatter over the rosemary, then season with salt and pepper. Toss to coat, then spread out in a single layer. TIP: Use two baking trays if necessary. 

When the oven is hot, roast on the top shelf until golden, 25-35 mins. Turn halfway through.

Meanwhile, peel and grate the garlic (or use a garlic press. Grate the Cheddar.

Trim the baby gem, then separate the leaves and reserve 1 leaf per person. Tear the remaining lettuce into bite-sized pieces. 

In a medium bowl, combine half the red wine vinegar with the sugar and olive oil for the dressing (see pantry for both amounts). Season with salt and pepper, then set aside.

In a large bowl, combine the garlic, breadcrumbs, salt and water for the breadcrumbs (see pantry for both amounts), then add the beef mince. Season with pepper and mix together with your hands. 

Roll into even-sized balls, then shape into 1cm thick burgers, 1 per person. TIP: The burgers will shrink a little during cooking. 

Halfway through cooking the wedges, pop the burgers onto a baking tray and bake on the middle shelf until cooked through, 12-15 mins. IMPORTANT: Wash your hands and equipment after handling raw mince. The burgers are cooked when no longer pink in the middle. 

Meanwhile, heat a drizzle of oil in a frying pan on medium-high heat.

Once hot, lay in the bacon rashers and fry until crispy and brown, 3-4 mins on each side. Transfer to a plate lined with kitchen paper. IMPORTANT: Wash your hands and equipment after handling raw meat. Cook bacon thoroughly.

Put the frying pan back on medium heat with a drizzle of oil. Once hot, add the onion and fry, stirring occasionally, until softened, 5-6 mins. 

In the meantime, halve the burger buns.

Once softened, stir the sugar for the onion (see pantry for amount) and the remaining red wine vinegar into the onions, then reduce the heat and cook until soft and sticky, 2-3 mins. Remove from the heat.

Meanwhile, once the burgers are cooked, carefully place the cheese on top of them and pop back into the oven until the cheese has melted, 2-3 mins. 

At the same time, pop the burger buns into the oven to warm through, 2-3 mins.

When everything's ready, spread a layer of caramelised onion over the bun bases. Top with the cheesy burgers, the crispy bacon, reserved baby gem leaves, then sandwich shut with the bun lids.

Sprinkle the truffle zest over the wedges. Add the torn baby gem to the dressing and toss to coat.

Serve your burgers with the wedges and salad alongside.

Enjoy!