For the starter dough, drain the tin of peaches/pears, reserving the juice. Place the fruit into a mixing bowl with 160ml/5fl oz of the reserved juice. Cover and leave to ferment at room temperature for two days.
Transfer the fruit and juice to a blender and blend to a fine purée. Strain the purée through a sieve into a jug.
Place the flour, yeast and fermented juice into a free-standing electric mixer fitted with a dough hook and mix on high speed until a smooth dough has formed.
For the cider rolls, place all the ingredients, except the salt, into an electric mixer fitted with a dough hook and mix on a high speed for six minutes. Add the salt and mix on for another two minutes. Transfer the dough to a floured bowl, cover with a damp cloth and leave in a warm place to rise for 30 minutes.
On a floured surface, knock back the risen dough then shape into ten rolls. Place the rolls onto a baking tray, cover with a damp cloth and leave to prove in a warm place until doubled in size, about 40 minutes.
Preheat the oven to 220C/450F/Gas 7.
Sprinkle the surface of the rolls with flour, then bake for 15-20 minutes or until golden brown and the bread sounds hollow when tapped on the underside.
Transfer to a wire rack and leave to cool before serving.
For the burger, heat a frying pan over a medium heat and add a drizzle of olive oil. Gently fry the shallots, garlic and chilies for two minutes, then remove to a plate and allow to cool.
Working in two batches, blend the whiting in a food processor for one minute, then transfer to a large bowl.
Add the shallot and chilli mixture, the parsley, eggs, breadcrumbs and some salt and pepper. Mix well, using your hands, until evenly mixed and well combined. (Fry a little piece of the mixture to taste for seasoning, adding salt and pepper as necessary.)
Divide the mixture into 100g/3½oz balls and mould them into patties. Place onto a plate, cover and refrigerate for 20 minutes or until ready to cook.
To cook the burgers, heat your oven to 200C/400F/Gas 6.
Heat a frying pan over a medium heat and add a good drizzle of olive oil. When hot, add the patties and fry for two minutes on each side. Transfer them to a baking tray and place in the oven for three minutes to finish cooking.
For the tartare sauce, place the egg yolks, vinegar, mustard, salt and lemon juice into a food processor.
Blend to combine, then with the motor still running, gradually add the rapeseed oil a little at a time.
Continue until all the oil has been added and the tartare sauce has thickened.
Spoon into a bowl, add the remaining ingredients and mix well.
Season with black pepper and a little more salt if necessary.
For the gherkin salad, mix the ingredients together then season with salt and freshly ground black pepper.
Split each roll in half. Drizzle the bottom halves with a little olive oil, then add some gherkin salad. Top with a whiting burger, then spoon on some tartare sauce.
The fermented starter dough will live in the fridge happily for up to five days.