Step 1Preheat oven to 200°C. Place the flour, icing sugar mixture, almond meal and chilled butter in the bowl of a food processor and process until mixture resembles fine breadcrumbs. Add the egg yolk and process until mixture just comes together. Turn on to a lightly floured surface and gently knead until just smooth. Shape into a disc. Cover with plastic wrap and place in the fridge for 30 minutes to rest.
Step 2Use a rolling pin to roll pastry to a 3mm-thick disc. Line a 22cm round (base measurement) fluted tart tin with removable base with the pastry. Cover with plastic wrap and place in the fridge for 30 minutes to rest.
Step 3Line pastry with baking paper and pastry weights, rice or dried beans. Bake in preheated oven for 8-10 minutes. Remove paper and weights, rice or beans and cook for a further 5 minutes or until golden brown and cooked through. Remove from oven and set aside to cool.
Step 4Combine the condensed milk, golden syrup and half the extra butter in a large saucepan over medium heat. Cook, stirring constantly with a wooden spoon, for 5-7 minutes or until golden in colour and caramel thickens. Remove from heat and immediately pour into the pastry case. Use a small palette knife to smooth the surface.
Step 5Place the chocolate and remaining extra butter in a heatproof bowl over a saucepan half-filled with simmering water and stir with a metal spoon for 5 minutes or until chocolate melts and mixture is glossy. Pour over the caramel and use the back of a spoon to smooth the surface. Set aside for 30 minutes to set. Decorate with gold leaf and cut into wedges to serve.