Preheat your oven to 220°C/200°C fan/gas mark 7. Remove the steaks from your fridge to allow them to come up to room temperature.

Chop the potatoes lengthways into 1cm slices, then chop into 1cm wide frites (no need to peel).

Pop the frites onto a large baking tray. Drizzle with oil, season with salt and pepper, then toss to coat. Spread out in a single layer. TIP: Use two baking trays if necessary.

When the oven is hot, bake on the top shelf until golden, 25-30 mins. Turn halfway through.

Meanwhile, halve, peel and slice the shallot as thinly as you can.

Pop into a small bowl and add half the balsamic vinegar and the sugar for the pickle (see pantry for amount). Add a pinch of salt, mix together and set aside to pickle.

Meanwhile, place the baguette on a medium baking tray.

When the frites are halfway through cooking, add the baguette to the middle shelf of your oven until golden and piping hot, 10-12 mins. Once baked, allow to cool, 5 mins.

While everything's in the oven, halve, peel and thinly slice the onion.

Heat a drizzle of oil in a medium frying pan on medium heat.

Once hot, add the onion, season with salt and pepper and fry, stirring occasionally, until golden, 10-12 mins.

Add the remaining balsamic vinegar and the sugar for the onions (see pantry for amount) and cook until caramelised, 1-2 mins more.

While the onion fries, in a small bowl, mix together the mayo and truffle zest. Cut the tomato into 2cm chunks.

Heat a drizzle of oil in a large frying pan on high heat. Season the steaks with salt and pepper.

Once hot, lay the steaks into the pan and fry until browned, 1 min on each side. Lower the heat slightly and cook for another 1-2 mins on each side if you want them medium-rare. TIP: Cook for 1-2 mins more if you like it more well done. IMPORTANT: Wash your hands and equipment after handling raw meat.

Once cooked, transfer to a board, cover with foil and allow to rest for a couple of mins. IMPORTANT: The steak is safe to eat when browned on the outside.

When ready to serve, slice the steaks widthways into 1cm thick slices.

Slice the baguette in half lengthways. Spread the truffle mayo onto the base, then top with the steak slices. Spoon over the caramelised onion and add a handful of the baby leaves.

Sandwich shut with the baguette lid, slice in half widthways and share between your plates.

Add the remaining baby leaves and tomato to the pickled shallot and toss together with a drizzle of oil. Serve your bistro style salad alongside with the frites.