Scatter the sugar into a 24cm ovenproof frying pan and add the cider, if using, and the cinnamon stick. Place on the heat and bring to the boil, then reduce the syrup until it caramelises and goes amber, then add the butter off the heat and toss through to make a sticky sauce. While the sauce is still warm, pack the pan with the apples and pears. Roll the pastry out until it’s slightly larger than the pan, then drape over the fruit and use a spoon to tuck the pastry under the fruit completely encasing them so that all you see is the puff pastry. Pop in the fridge for an hour or overnight.