Melt the butter with the sugar in a large frying pan and cook until the sugar has dissolved and the mixture has become a golden-brown caramel.
Add the pear halves and cook, turning once, until caramelised all over. Remove from the heat and set aside.
Preheat the oven to 180'C.
Place the 225g plain flour, 100g butter and 25g sugar into a food processor and pulse together until the mixture resembles breadcrumbs.
Add the egg and the milk and pulse until the mixture just comes together as a dough.
Remove the dough from the food processor and roll to form a ball. Wrap in cling film and chill in the fridge for 40 minutes.
Remove the dough from the fridge and unwrap. On a clean, floured work surface roll out the pastry and line a 20cm tart tin.
Transfer to the oven to bake for 10 minutes or until golden-brown.
Mix 100g butter and 225g sugar together in a bowl until light and fluffy.
Add the eggs to the butter mixture one at a time and and incorporate each one before adding the next (this can be done in a food mixer).
Add the lemon zest, 50g plain flour and ground almonds. Mix well.
Spoon the filling into the baked pastry tin and press the caramelised pear halves into the filling, so that they are half-submerged.
Transfer to the oven and bake for 30 minutes, or until the filling is cooked through.
Zest the lemon. Halve the vanilla pod and scrape out the seeds. Sift the icing sugar into a bowl and beat together with the mascarpone, the lemon zest and the vanilla.
Remove the warm cake from the tin and cut into wedges. Serve with a dusting of icing sugar or cocoa powder and finish with a spoonful of cream.
«If you are making the cake ahead of time, keep it in the tin at room temperature and then warm through in the oven at 140'C for about 8 minutes before serving. »