Pour flour, salt and sugar in a bowl and combine. Add diced butter and mix by hand to obtain a crumbly mixture. Add egg and water to mix well to obtain a smooth dough.
Roll on the dough and spread out in a lightly greased pie pan (9 inch pan). Cover with plastic wrap and chill in the fridge for about an hour.
Preheat oven on 420F
For the filling, wash the redcurrants and let them dry.
Crumble the biscotti and cut the white chocolate into small-ish dices
Combine eggs, cream, white chocolate, sugar and vanilla sugar.
Spread out the crumbled biscotti on the dough. Add the redcurrant then pour the wet mixture.
Bake for 20-25 minutes. Let cool and decorate with slices of almonds