The Grill's chips with gravy mayonnaise

Firstly, make sure you have 2 identical deep dishes as it is important the terrine is pressed properly. Preheat an oven to 190ºC/170ºC fan/gas mark 5

Peel and slice the potatoes finely using a mandoline. Sprinkle the salt over the sliced potato and mix well to combine. Leave for a few minutes whilst you line one of your dishes with baking paper

Layer up the potatoes in neat rows. Every couple of layers, sprinkle with an even dusting of cornflour – this helps the layers to form a solid block later

Place the second tray or dish on top of the layered potatoes. Turn both upside-down over a tray (or sink) and push down to extract as much liquid as possible – you really want to squeeze as much water out of the potatoes as you can at this point, so be firm!

Turn the dishes back over and remove the top dish. Use a small knife to pierce several holes in the potatoes and pour over the warm clarified butter so that it is evenly distributed throughout the terrine. Cover with a sheet of baking paper and 2 sheets of tin foil and seal well

Place in the preheated oven and cook for 2-3 hours, checking on progress after the second hour. It should cut through easily with a small knife when ready

Once cooked, it needs to be pressed. Place the dish into a larger tray (to catch any over-spilled butter) then place the second tray from earlier on top and weigh it down, ideally with something 4 times the weight of the terrine. Place in the fridge and leave to press and set for 2 days

After 2 days and when you're ready to cook, carefully remove the set potato block from the dish and cut it into 8x2x2cm ‘chips’

Bring a deep-fat fryer or pan of oil to 180ºC and cook the chips for around 4-5 minutes until golden brown. Work in batches to ensure the temperature of the oil doesn't drop. Drain on kitchen paper and season with salt

To make the mayonnaise, simply whisk the gravy into the mayonnaise until evenly combined. Taste and season with salt and vinegar if needed, then serve with the chips