The tarts I grew up with in South Australia were light on the apple and heavy on the custard, but these days I prefer it the other way around.
1½ cups (225g)
50g caster sugar
½ tsp ground cinnamon, for dusting
4 Granny Smith apples, peeled, cored and cut into 2cm cubes
juice of ½ a lemon
1 tsp cornflour
60g caster sugar
1¾ cups milk, warmed
1 tsp vanilla extract
Combine the flour, butter and sugar in a food processor and pulse to form coarse breadcrumbs. Add 1½ tablespoons of iced water and pulse until the dough starts to form a ball. Knead just 2 or 3 times to bring the dough together, then wrap the dough in plastic wrap and refrigerate for 20 minutes.
Heat oven to 200°C. Roll out the dough to a ½ cm-thick sheet and press into a 22cm fluted tart tin. Put in the freezer for 10 minutes to firm, then line with baking paper, top with pastry weights and bake for 10 minutes. Remove weights and bake for a further 5 minutes. Allow to cool to room temperature in the tin.
For the apple filling, core and cut the apples and toss the pieces immediately in the lemon juice to prevent them browning. Put sugar and 50ml water into a medium saucepan and cook over high heat until the sugar is dissolved. Add the apples and cornflour and stir to coat in the sugar. Reduce the heat to low, cover and cook for about 10 minutes, stirring occasionally, until the apples have softened to a chunky jam. Allow to cool to room temperature, then press into the base of the tart tin and refrigerate until firm, about 30 minutes.
Heat your oven to 160°C. For the custard, whisk the eggs and caster sugar together until the sugar is completely dissolved. Whisk in the warm milk a little at a time and whisk through the vanilla. Pour the custard mixture over the pie, dust with the cinnamon and bake for about 30 minutes until the custard is beginning to firm (test by tapping the pan and watching the ripples in the centre of the custard). Allow to cool to room temperature, then serve.
Adam's tip: When you need a shortcrust pastry to hold liquid (like custard), it's worth adding a little more water to the mix. The wetter dough will be easier to roll and more resistant to cracks that would let liquid seep through.