Method

• 1.
  Place flour, lemon rind, sugar and butter in a food processor and whiz until fine crumbs form. Then, with motor running, slowly add the iced water until a dough forms. Tip out onto a piece of plastic wrap and shape into a rectangle, then enclose and chill for 30 minutes.
• 2.
  Working quickly, roll pastry out between 2 sheets of baking paper to a 4mm-thick, 34cm x 26cm rectangle. Remove top piece of paper and transfer dough to a 20cm x 28cm x 2.5cm-deep rectangle flan pan with a removable base. Using the remaining piece of baking paper as an aid, gently press pastry into corners, trimming excess. Prick base all over with a fork. Freeze for 15 minutes or until firm (this helps stop the pastry shrinking).
• 3.
  Meanwhile, place a baking tray in the oven and preheat oven to 200°C/180°C fan-forced. Line the frozen tart shell with baking paper, then fill with baking weights. Bake on preheated tray in oven for 25 minutes or until light golden around edges and starting to cook at the centre. Remove baking paper with weights, then bake for a further 20-25 minutes or until cooked and golden. Transfer tart shell, on baking tray, to a wire rack and cool completely.
• 4.
  Wrap tightly in plastic wrap and store at room temperature overnight. Meanwhile, for the ginger lemon syrup, place all ingredients and 1/2 cup (125ml) water in a small saucepan over medium heat. Cook, stirring, until sugar dissolves, then simmer for 10-12 minutes until mixture reduces by two-thirds. Remove pan from heat, set aside to cool to room temperature, then transfer to an airtight container and store at room temperature overnight. Strain before serving.
• 5.
  For the white choc mascarpone, place chocolate and cream in a medium heatproof bowl over a small saucepan of gently simmering water (don’t let the bowl touch the water) and stir until melted and smooth. Remove bowl from heat and cool to room temperature, stirring occasionally, for 30 minutes. Stir through mascarpone, then cover and chill overnight until firm.
• 6.
  To serve, transfer the tart shell to a serving platter, spread with white choc mascarpone, scatter with blueberries and raspberries, drizzle with the ginger lemon syrup, and top with flowers (if using).