Crust: Put the butter into the freezer 15 minutes ahead of time. In a large bowl, mix together flour, sugar, and salt. Using your hands, mix in the butter until the mixture resembles pea-sized crumbs. Drizzle water over the dough and bring together, gently knead the dough a few times in the bowl until it all comes together. It is important not to handle the dough too much. (Add 1-2 tablespoons of water if the dough seems dry.) Flatten the dough into a disk, wrap tightly in plastic wrap and cool in the refrigerator for 1 hour.

Filling: In a large bowl, combine sliced peaches, blueberries, lemon juice, sugar, cornstarch, vanilla, cinnamon, and salt. Gently toss to coat the fruit evenly.

Preheat oven to 190 C (370 F). Line a large baking sheet with parchment paper or a silicone baking mat.

Unwrap and place the dough between 2 sheets of parchment paper and use a rolling pin to flatten it into a 30 cm (12 inch) circle. Transfer dough to the prepared baking sheet.

Spoon the fruit into the center of the dough, leaving a 5 cm (2 inches) border all around. Gently fold the edges of the dough over the fruit to make a rim, overlapping the dough as necessary.

Brush the crust with the beaten egg and sprinkle with sugar. Bake for 25-35 minutes or until the crust is golden brown.

Remove from the baking sheet and leave to cool slightly. Serve with a scoop of vanilla ice cream.