For lemon curd ice-cream, whisk 2 yolks and half the sugar in a bowl to combine, then whisk in lemon juice. Transfer to a saucepan, add butter and stir continuously until mixture thickly coats the back of a wooden spoon (6-8 minutes). Transfer to a bowl, cover closely with plastic wrap and refrigerate until chilled (3-4 hours). Bring cream, milk, lemon thyme and vanilla bean and seeds to the simmer in a saucepan over medium-high heat. Whisk remaining egg yolks and remaining sugar until thick and pale (2-3 minutes) then, whisking continuously, pour hot cream mixture into egg mixture. Transfer to a small clean saucepan and stir continuously over low-medium heat until mixture thickly coats the back of a wooden spoon (6-8 minutes). Pour into a bowl placed over ice and stir occasionally until cold. Cover and refrigerate to chill and infuse (4 hours), then strain mixture through a fine sieve (discard solids). Churn in an ice-cream machine, then transfer to a container, swirl in lemon curd and freeze until required. Makes about 700ml. Ice-cream will keep in the freezer for 3 months.
Beat 65gm butter and icing sugar in an electric mixer until pale (2-3 minutes). Scrape down sides of bowl, then add egg and yolk, beating well to combine. Add flour and a pinch of salt, and mix to just combine, then form into a disc, wrap in plastic wrap and refrigerate until firm (1 hour).
Preheat oven to 180C. Roll out dough on a lightly floured surface to about 2mm thick, cut out twenty-four 6cm-diameter rounds, then press into two 12-cup mini muffin tins. Refrigerate to rest (30 minutes). Dock base of pastry cases with a fork, bake until golden and cooked through (6-8 minutes), cool slightly in tin then remove from tin and cool on a wire rack.
For lemon sherbet, combine ingredients in a dry bowl and set aside until required. It’s important the bowl is completely dry otherwise the sherbet will lose its fizz.
Combine 80gm blueberries, caster sugar and 1 tbsp water in a small saucepan over low heat, squash blueberries with a fork and cook, stirring occasionally, until juices are released and mixture is a deep purple colour (2-3 minutes). Remove from heat, add remaining blueberries, lemon juice and remaining butter, stir to melt butter and set aside to cool. To serve, spoon blueberry mixture into pie shells, top with scoops of lemon curd ice-cream and dust with sherbet.