Place flour and icing sugar in the bowl of a food processor.
Roughly chop butter and add to the flour, mixing to a breadcrumb consistency.
Add egg and pulse until mixture comes together- if needed, add a small amount of chilled water.
Wrap pastry in plastic cling film and refrigerate for 30 minutes.
Preheat oven to 180¡C. Roll pastry out to about 3mm thick and line a 28cm tart pan.
Bake pastry with baking paper, then place rice or dry beans on top and bake blind for 15 minutes.
Remove covering and cook for a further 5 minutes until pastry is lightly golden.
Reduce heat to 160C.
Place cream, milk, brown sugar, cocoa and chocolate in a small saucepan.
Stir over a gentle heat until chocolate has melted and mixture is smooth.
Allow to cool until just warm.
Whisk eggs and combine with chocolate mixture.
Pour filling into tart shell and cook for 30 minutes until tart is just set but still slightly wobbly in the centre. Allow to cool and serve at room temperature.
