Cheesy Beef Burger & Truffle Mayo

While the fries are baking, pick and finely chop the rosemary leaves. Thinly slice the brown onion. In a large bowl, combine the beef mince, fine breadcrumbs (see ingredients list), salt, egg, 1/2 the rosemary and a good pinch of pepper. Shape the beef mixture into evenly sized patties (1 per person), slightly larger than your burger buns. Set aside.

Place the grated Parmesan cheese in even circles (about the same size as your buns, 1 per person) on a second oven tray lined with baking paper. Bake until the cheese is golden and crisp at the edges, 6-8 minutes. TIP: Keep an eye on them, they can burn quickly! Remove from the oven and set aside – the Parmesan crisps will become crisp as they cool.

While the Parmesan crisps are baking, in a medium frying pan, heat a drizzle of olive oil over a medium-high heat. Add the onion and remaining rosemary and cook, stirring often, until softened, 4-5 minutes. Add the balsamic vinegar, water and brown sugar and mix well. Cook until dark and sticky, 3-5 minutes. Transfer to a small bowl.

Wipe out the frying pan and return to a medium-high heat. Add the beef patties and cook until just cooked through, 4-5 minutes each side. While the burgers are cooking, place the bake-at-home burger buns on a wire rack in the oven until heated through, 3 minutes. Thinly slice the tomato.