In a large mixing bowl, combine the flour, sugar, salt and stir to mix. Scatter the butter cubes and shortening pieces over the flour mixture.
Using a pastry blender or two forks cut in the butter and shortening until the mixture forms small large coarse crumbs.
Drizzle the ice water over the mixture and toss with the fork until the dough is evenly moist and begins to come form large clusters, but doesn't form a ball.
Transfer the pie dough to a clean work surface. Using floured hands, gently work the dough enough just to form a ball.
Shape the dough into into a disc and wrap tightly in cling film or plastic wrap. Refrigerate for at least 1 hour or overnight.
In a large mixing bowl, stir peaches, brown sugar and amaretto. Leave to marinate for 30 minutes.
Pre-heat oven to 180°C F/200°C/400°F. Line a large baking pan with baking or parchment paper.
Remove the dough from fridge. If it is too cold to roll out, let it stand at room temperature for 10 minutes. Lightly flour a work surface. Roll out the dough into a 12 inch circle (it doesn't have to be perfect). Trim off any ragged edges to make a clean even circle, if desired. Carefully use the rolling pin to transfer the dough onto the prepared baking sheet.
Leaving a 2 inch ( 5 cm) border, arrange the peaches( not the juices) in the centre of the dough. Fold the edges up and over the filling, forming loose pleats all around the edge. Mix the juice left in the bowl with corn starch and pour over the fruit. Brush the pleated dough with egg wash and sprinkle it with flaked almonds.
Bake for 30-35 minutes. Transfer to a wire rack and leave to cool before slicing and serving. Serve warm or at room temperature,