Work the mince in a bowl with your hands to break down the fat – this will act as a natural binder and help the mince stick together.
Divide the meat into 4, roll each piece into a ball, then flatten to roughly 1cm thick, so they’re slightly larger than the buns (they’ll get thicker as they cook). Pop in the fridge to chill for 30 minutes.
When you’re ready to cook, preheat the oven to 120°C/250°F/gas ½.
In a small bowl, mix the brown, Worcestershire and tomato sauces together – adding as much or as little of each as you like. Peel, finely chop and stir in the shallots, then set aside.
Halve the buns, then pop them on a baking tray and warm in the oven for 8 to 10 minutes.
Meanwhile, heat a drizzle of oil in a large non-stick pan over a medium-high heat and fry the burgers for about 4 minutes on each side, or until cooked through, seasoning well as you go.
To build your burgers, spread the shallot sauce on the warm bun bases. Slice and add the crisp apple, followed by the burger and a nice piece of blue cheese. Finish with a pinch of watercress, then pop on the lids and serve immediately.