Salted Chocolate And Walnut Tart

To make the pastry, cream the butter and sugar together until combined. Add the egg yolks, one at a time, and mix until incorporated. Add the combined flour and cacao and mix until just combined.
Using your hands, press the dough into a 22 cm tart tin, trying to achieve an even ½ cm layer, over the base and sides (you may have a small amount of pastry left over). Use a round-sided glass to roll around the base of the tart to even the pastry out if necessary. Place the tart shell in the fridge for 20 minutes to chill.
Preheat the oven to 200˚C.
Line the pastry with baking paper and fill with baking beads or weights. Bake blind for 20 minutes, remove the weights and paper and bake for a further 5–7 minutes until dry. Remove from the oven and allow to cool before returning to the fridge to chill. Reduce the oven to 180˚C.
To make the filling, place the chocolate, cream, sugar and salt flakes in a heatproof bowl. Place the bowl over a pan of gently simmering water for 7–8 minutes until melted. Pour the filling into the chilled tart shell and leave to cool before returning to the fridge to chill for a further 3–4 hours until set.
To make the walnut praline, roast the walnuts in the oven for 8–10 minutes until golden. Roughly chop and place on a baking paper lined tray. Combine the sugar and 2 tbsp water in a small saucepan and place over a low heat. Cook, stirring, until the sugar dissolves then increase the heat to high and bring to the boil, brushing down the sides of the pan a few times with a wet pastry brush. Cook for 6–7 minutes until the sugar begins to change colour. Reduce heat to medium-high and cook until the sugar turns a medium golden colour. Immediately tip the caramel over the walnuts and allow to set. Once hard, chop into small pieces and sprinkle over the top of the tart.
Cut into small slices and serve.