• 200g (1 1/3 cups) plain flour
  • 125g unsalted cold butter, finely chopped
  • 2 tablespoons icing sugar
  • Finely grated zest of 2 blood oranges
  • 1 egg yolk combined with 1 tablespoon iced water
  • 1 teaspoon vanilla extract
  • 6 blood oranges
  • 165g (3/4 cup) caster sugar
  • Step 1 Process flour, butter, sugar, half the zest and a pinch of salt until mixture resembles breadcrumbs. Add yolk mixture and vanilla. Process until mixture just comes together. Form into a rectangle, wrap in plastic wrap and refrigerate for 30 minutes.
  • Step 2 Roll out pastry on a sheet of lightly floured baking paper until 4mm thick and line an 11cm x 34cm rectangular tart tin with removable base. Trim pastry 5mm above rim of tin, then freeze for 1 hour.
  • Step 3 Preheat oven to 180C. Line pastry with baking paper, fill with dried beans or rice, place on an oven tray and bake for 15 minutes. Remove paper and beans, and bake for 15 minutes or until golden and dry.
  • Step 4 For pastry cream, slowly bring milk and vanilla to the boil in a pan. Combine flour and sugar in a bowl, then whisk in milk until smooth. Return mixture to pan and stir until thick, then stir for a further 3 minutes to 'cook out' the flour taste.
  • Step 5 Meanwhile, soak gelatine in cold water for 5 minutes. Squeeze out excess water. Whisk yolks into milk mixture and stir for 1 minute, then stir in gelatine until dissolved. Remove from heat and whisk in butter and remaining zest. Cover surface closely with plastic wrap. Cool to room temperature.
  • Step 6 Remove peel and pith from 5 oranges, then cut flesh into 5mm-thick slices.
  • Step 7 Half-fill a large bowl with water. Place sugar and 60ml (1/4 cup) water in a small pan and simmer over medium heat until a golden caramel. Dip base of pan into the bowl of water to stop the cooking. Cool for 2 minutes, then drizzle base of tart with enough caramel to lightly coat. Add juice from half the remaining orange to caramel in pan. Stir over low heat until smooth.
  • Step 8 Fill tart shell with pastry cream and top with orange slices. Drizzle over syrup, then place tart in freezer for 10 minutes to firm and harden caramel before serving.