For orange ice-cream, finely grate rind of 2 oranges and set rind aside. Peel all oranges, remove pith, coarsely chop flesh and transfer to a saucepan. Wrap any seeds in muslin and add to pan along with lemon juice and 220gm sugar. Bring to the boil over medium-high heat, stir to dissolve sugar, reduce heat to medium and cook, stirring occasionally, until light caramel in colour (25-30 minutes). Cool completely. Bring cream, milk, vanilla bean and seeds and reserved orange rind to the simmer in a saucepan over medium-high heat. Whisk yolks and remaining sugar in a heatproof bowl until pale (2-3 minutes), then pour in cream mixture and whisk to combine. Return to pan, stir until mixture thickly coats a spoon (5-6 minutes), strain into a bowl and whisk occasionally until cool. Refrigerate until chilled. Freeze in an ice-cream machine and add half the orange jam (reserve remainder) when mixture is almost firm. Transfer to a container and freeze. Makes about 1 litre.
For sweet orange pastry, process flour, sugar, orange rind and a pinch of salt in a food processor to combine. Add butter, process to a sand-like texture, then add yolk and process until mixture just comes together. Turn onto a lightly floured bench, form into a disc, wrap in plastic wrap and refrigerate to rest (1 hour).
Meanwhile, melt chocolate and butter in a heatproof bowl over a saucepan of simmering water. Stir occasionally until smooth, then set aside. Whisk eggs, sugar and liqueur in a heatproof bowl over simmering water until thick and pale and mixture holds a ribbon (10-15 minutes). Remove from heat, fold in chocolate mixture, then sieve in flour and cocoa and fold to combine. Set aside.
Preheat oven to 180C. Roll out pastry on a lightly floured surface to 3mm thick, line the base and sides of a 22cm-diameter loose-bottomed tart tin, trim edges and refrigerate to rest (30 minutes). Blind bake until light golden (10-12 minutes), remove paper and weights and bake until crisp (8-10 minutes), then set aside.
Spoon chocolate mixture into tart case, filling to 5mm below rim, and smooth top. Bake until puffed and set around edges (15-20 minutes), then remove from oven and stand for 10 minutes. Dust with cocoa and serve warm or at room temperature with orange ice-cream and warmed remaining orange jam.
This recipe is from the May 2013 issue of Australian Gourmet Traveller.