Preheat the oven to 175°C.
Crush the shortbread biscuits in a plastic bag with a rolling pin and tip crumbs into a bowl.
Mix the crumbs with melted butter and press into the base of a 25cm spring-form tin.
Pulse the cream cheese, ricotta, eggs, sugar, and vanilla seeds in a food processor until smooth.
Melt the white chocolate in a heatproof bowl over simmering water and allow to cool slightly.
Fold the chocolate into the cheese mixture, pour into the tin, and bake for 50 to 60 minutes.
Cool the cheesecake, remove from the tin, and serve with berries, cream, and extra drizzled chocolate.