Meanwhile, use an electric mixer to thoroughly whisk the double cream until it forms stiff peaks. Add the cream cheese, icing sugar, diced strawberries and vanilla, and mix again on a lower speed until well combined. Spoon the mixture on top of the cheesecake base, and smooth out the top. Decorate the top of the cheesecake with additional strawberries if desired. Leave in the fridge for at least a few hours, until firm.