Chocolate, orange and frangipane tart

Method

1. For the pastry, put the flour, butter and a pinch of salt in a food processor, then pulse to a fine breadcrumb consistency. Beat the egg with the cold water, then add to the flour and butter mixture, pulsing until the mixture starts to come together in large clumps. (If you don’t have a food processor, rub the butter into the flour and salt in a mixing bowl using your fingertips, then add the egg and water and mix together quickly until the mixture begins to form a dough.) Turn out onto a lightly dusted work surface, then knead gently to bring the dough together. Shape into a disc, wrap in cling film, then chill for 1 hour.
2. Roll out the chilled pastry on a lightly floured surface into a 29-30cm circle, about 3mm thick. Loosely roll the pastry around a flour-dusted rolling pin, then lift into the tart tin and press gently into the edges. Trim off any excess pastry and chill again for 30 minutes.
3. Heat the oven to 200°C/180°C fan/gas 6. Prick the pastry all over with a fork, line with non-stick baking paper and fill with ceramic baking beans or uncooked rice, then bake for 15 minutes. Remove the paper and baking beans/rice, then bake for a further 5-10 minutes until the pastry feels sandy and there are no grey patches. Set aside to cool (see Make Ahead). Leave the oven on.
4. In a medium mixing bowl, beat the butter for the frangipane until creamy and soft. Add the icing sugar, flour and ground almonds, then mix until combined. Add the eggs, orange zest and rum, then mix until smooth (see Make Ahead). Pipe or spoon the mixture into the tart case, levelling with a spoon or palette knife. Return to the oven for 25-30 minutes until the frangipane is just set. Put on a cooling rack and set aside to cool completely.
5. To make the ganache, put both chocolates in a metal mixing bowl. Heat the cream in a saucepan until just boiling, then immediately pour over the chocolate and leave to stand for 30 seconds without touching it. Gently stir the cream and melted chocolate together, starting at the centre and gradually bringing in the mixture at the edges of the bowl. Once combined, add the butter and mix again until fully incorporated. Add the orange zest and a pinch
   of salt, give it a final stir, then leave to cool and thicken at room temperature for about 30 minutes, stirring very occasionally. Don’t put the ganache in the fridge.
6. When the ganache is thick but still pourable, pour it into the tin on top of the frangipane. Gently tap the tart on your worktop to level the top and get rid of air bubbles, then put in the fridge to set for at least 3 hours or overnight.