For the crust: Rub together flour, salt, butter and sugar until the mixture is crumbly. Gradually add ice cold water to form the dough. Do not knead. Wrap in plastic wrap and chill for 30 minutes.
For the filling: Mix fruit, cornstarch, sugar and lemon juice and reserve.
Preheat oven at 190°C/370°F. Roll out the dough into a circle on parchment paper (or on a floured surface) and place it on a baking sheet. Place the peaches in the center leaving a 1-inch border. Fold up the edges of the dough around the filling, and gently pleat to seal. Brush the edges with egg wash and sprinkle with sugar. Bake for 25-30 minutes until it is bubbly and the edges are golden. Serve warm with whipped cream or an ice cream scoop.
