Preheat the oven to gas 6, 200C, fan 180°C Unroll the pastry and use a 10cm fluted pastry cutter to cut 12 circles and use to line a 12-hole bun tin, pressing each firmly up the sides of each. Freeze for 20 minutes, or until really cold.
Put a small piece of scrunched baking paper into each pastry circle and fill with baking beans. Bake in the oven for 10-12 minutes until the edges are golden, then remove the paper and beans and bake for 2-3 minutes. Cool in the tin for 5 minutes, then transfer to a rack to cool completely.
To make the curd, put the orange juice and zest into a small pan with 150ml cold water and the sugar. Mix the cornflour with 3tbsp water. Gently heat the juice and zest until warm, then remove from the heat and pour in the cornflour mixture, stirring immediately. Return to the heat and stir continually until mixed in completely. Remove from the heat and transfer to a heatproof bowl, cover with clingfilm to prevent a skin from forming and set aside to cool completely.
Once the curd is cool, spoon into the cold pastry cases and decorate each with a small orange segment, 2 small mint leaves, 3 blueberries and some orange zest. Dust with a sprinkling of icing sugar.