Raspberry meringue pie

Pre-heat the oven to 190°C/375°F/gas mark 5.
Blitz the raspberries in a blender and pass through a fine sieve, discarding the seeds.
In a small bowl mix the cornflour, 75g of the caster sugar and the lemon juice together. Add this mixture to the raspberry puree.
In a pan slowly bring the puree to a simmer, stirring constantly until thickened.
Allow the raspberry mixture to cool slightly and beat in the egg yolks and butter.
Leave to cool completely.
Spoon the mixture into the pastry case, spreading it evenly.
In a clean bowl whisk the egg whites until stiff and then gradually whisk in the remaining caster sugar until you have a glossy thick meringue mixture.
Heap the meringue over the raspberry mixture and bake for 10-12 minutes until golden.