To make the Pastry: Sift flour, salt, cinnamon and sugar together, then transfer to the bowl of a food processor fitted with the chopping blade. Add butter and process briefly until the mixture resembles coarse breadcrumbs. Add water through the feed tube and pulse until mixture gathers in large clumps. Tip dough onto a dry, lightly floured surface and knead until smooth. Wrap in plastic wrap and refrigerate for 30 minutes, or until firm.
Preheat oven to 180°C (350°F). Roll out pastry to a 30 cm (11–12 in) round on a lightly floured surface. Transfer to a baking sheet (tray) lined with baking (parchment) paper.
To make the filling, halve apricots and remove stones. Toss apricots with lemon juice in a bowl and leave them to macerate (soften and soak up flavour) for 5 minutes. Mix in the first measure of caster sugar, the lemon zest and flour and pile fruit into the centre of the pastry. Fold in pastry edges by about 4 cm (1½ in), pinching the dough together to make it stay in place.
Scatter a few almonds on top of the apricots. Mix remaining almonds with the beaten egg white and paste them onto the outside of the pastry edging. Sprinkle pastry with a little caster sugar. Bake tart for 35–40 minutes, or until the pastry is golden and the fruit tender. Dust with icing sugar before serving.!