Method

• 1.
  For the pastry, whiz flour, almond meal, icing sugar, baking powder and a pinch of salt flakes in a food processor until combined. Add butter and zest and whiz until a crumb texture. Add egg yolk and\ 3-4 tbs cold water and process until dough forms a ball. Divide pastry into two-third and one-third portions. Enclose each in plastic wrap. Chill for 30 minutes.
• 2.
  Place peach and sugar in a large saucepan over medium-high heat. Cook, stirring, for 6-8 minutes until sugar dissolves and fruit starts to break down (cooking time will vary depending on ripeness of peaches). Mix cornflour with lemon juice in a small bowl until dissolved. Add to pan and stir to combine. Transfer to a bowl and chill until cool.
• 3.
  Roll out larger pastry portion between 2 sheets of baking paper into a 31cm round and use to line a 22cm, 2cm deep, loose-based tart tin. Trim any excess pastry. Chill for 30 minutes.
• 4.
  Preheat oven to 200°C/180°C fan-forced. Roll out remaining pastry between 2 sheets of baking paper to a 30cm round. Cut into 2cm-thick strips. Spoon peach mixture into tart shell.
• 5.
  Arrange half the pastry strips at 2cm intervals across top of tart. Repeat crossways with remaining strips. Press edges to seal and trim any excess. Lightly beat egg white and brush over pastry. Bake for 40 minutes or until golden brown. Set aside to cool completely in pan. Serve with mascarpone.