Sift the flour and icing sugar into a bowl. Add the butter and rub in with just your fingertips until the mixture is fine and crumbly. Stir in the ground almonds, then add almost all the water and stir into the flour mixture with a flat-bladed knife until the mixture forms a dough, adding the remaining water if necessary.
Turn the dough onto a lightly floured work surface and gather together into a ball. Roll out on a sheet of baking parchment into a circle about 26cm/10 1⁄2in in diameter. Flatten slightly, cover with cling film and refrigerate for 20 minutes.
Preheat the oven to 200°C/400°F/Gas mark 6.
Spread the cherries in the bottom of a greased 23cm/9in pie dish.
Cover the pie dish with the pastry, and trim the overhanging edge. Brush the pastry top all over with beaten egg, and sprinkle lightly with caster sugar. Put the pie dish on a baking tray, and cook for 35–40 minutes until golden brown.
Serve warm with cream or ice cream.