Caramelised onion potato rösti

Start by caramelising the onions. Heat half of the butter and oil in a large frying pan over a medium-low heat. Add the sliced onions to the pan with a pinch of salt and place a disc of baking paper on the top (a cartouche) and cook gently for 20-25 minutes, stirring occasionally, until completely soft but not coloured

Meanwhile, for the rösti mix, place the grated potato in a large bowl with a generous pinch of fine salt. Set aside for 10 minutes. Place the potato in a muslin cloth or clean tea towel and squeeze to remove as much excess moisture as possible. Transfer to a large dry bowl and separate the strands

Turn up the heat on the onions and cook for 10 minutes until deeply caramelised and golden, stirring regularly. Add the vinegar and sugar and stir to combine, then spread onto a tray to cool

For the herby soured cream, combine all the ingredients in a small bowl. Set aside in the fridge until needed

Add the cooled onions, grated Comté, thyme, egg, cornflour and a small pinch of salt and pepper and mix thoroughly

Divide into 6 (about 150g each) and use a 8.5cm pastry cutter, if you have one, to help shape the mixture into röstis about 2cm thick. Chill in the fridge for at least 30 minutes to firm up

Heat the remaining butter and olive oil in a large non-stick frying pan over a medium heat. Fry the röstis for 3-4 minutes, working in batches if needed to prevent overcrowding, then flip and continue cooking for a further 3-4 minutes, basting with the butter, until cooked through

Remove to a tray and rest for 5 minutes

To serve, divide the soured cream between 6 plates and top with the röstis. Garnish with the some extra finely chopped chives and parsley and serve immediately