When life gives you sour cherries - or rather, you accidentally pick up what look to be the most delicious cherries but which turn out to be mouth-puckeringly sour - you make sour cherry galette. Best of all it takes literally five minutes and endlessly adaptable to whatever is at hand in whatever quantity. In short, a circle of shortcrust pastry, sour cherries mixed with two tablespoons of sugar and a tablespoon of cornflour to absorb some of the juice and "pie-up" the filling. A milk or egg wash and in the oven for thirty minutes. Winning.