For the pastry, beat the butter and sugar in a large bowl until just mixed. Break in a whole egg and a yolk (keep the white for glazing later). Beat together for just under 1 min – it will look a bit like scrambled egg. Now work in the flour with a wooden spoon, a third at a time, until it’s beginning to clump up, then finish gathering it together with your hands. Gently work the dough into a ball, wrap in cling film, and chill for 45 mins. Now mix the 140g/5oz sugar, the cinnamon and flour for the filling in a bowl that is large enough to take the apples later.