To make the pastry, place all the ingredients except for the egg yolk and ice water in the bowl of a food processor and pulse until the mixture resembles rough breadcrumbs.
Add the egg yolk and pulse again.
Now add the water, tablespoon by tablespoon, whilst mixing, until the dough comes together in a ball.
Remove the dough from the food processor and wrap in clingwrap.
Place in the fridge to cool for at least 30 minutes.
Remove the cold dough from the fridge and roll out. Cut into circles big enough to fit your tart cases, press into the cases and return to the fridge for at least 30 minutes.
When you are ready to bake them, pre-heat the oven to 180°c and blind bake (line pastry with baking paper and fill with beans) for 7-10 minutes. Remove the baking paper and beans and bake for another 5 minutes.
Remove the tart shells from the oven and allow to cool.
To make the filling, whip the cream until soft peaks form. Slowly, while whisking, add the melted white chocolate and whisk until the cream is thick and glossy.
Place a spoonful of the white chocolate cream in each tart shell and top with fresh berries.