Bring milk to the simmer in a large saucepan over medium heat, add lemon juice, reduce heat to low and stir slowly until curds start to form (1-2 minutes). Remove from heat, set aside to cool, carefully spoon curds into a muslin-lined sieve placed over a large bowl and refrigerate until whey drains (overnight; discard whey).
For sweet pastry, pulse flour, icing sugar and 1 tsp fine sea salt in a food processor to combine. Add butter, pulse until fine crumbs form, then add yolks and pulse to combine. Turn onto a work surface, bring together with the heel of your hand, form into a disc, wrap in plastic wrap and refrigerate to rest (1 hour). Roll out on a lightly floured surface to a 24cm-diameter round and line a 22cm-diameter tart tin. Trim edges and refrigerate to rest (40 minutes).
Preheat oven to 180C. Blind bake pastry until edges are golden (10-12 minutes). Remove paper and weights and bake until base is golden and crisp (6-8 minutes). Set aside.
Meanwhile, combine currants, raisins and apera in a small bowl and set aside until fruit is plump (30 minutes). Beat butter and sugar in an electric mixer until pale and creamy, then add eggs one at a time, beating until incorporated. Fold in curd, currant mixture, breadcrumbs and nutmeg, spoon into pastry case and smooth top. Bake until golden (20-25 minutes), cool to room temperature and serve.
Note Sherry-style fortified wine made in Australia is now known as apera.
This recipe is from the June 2012 issue of Australian Gourmet Traveller.