Double line six ramekin dishes with cling film, leaving plenty of overhang. Combine the butter and biscuits in a bowl then divide equally between the prepared ramekin dishes and press down with the back of a teaspoon to form a base. Chill in the fridge while you work on the filling.
In a saucepan over a medium heat, combine 150g of raspberries with the caster sugar and lemon juice. Cook and mash over a low heat for 10 minutes until soft. Purée then press through a sieve into a clean saucepan. Soak the gelatine leaves in cold water for 5 to 6 minutes then drain and squeeze any excess liquid out. Add to the raspberry purée and cook over a low heat until dissolved.
In a mixing bowl whisk the cream cheese together with the yoghurt and vanilla extract until light and fluffy. Add the raspberry mixture. Divide equally between the 6 ramekin dishes and smooth the top. Chill in the fridge for 6 hours to achieve a good set.
When ready to serve, half the remaining raspberries and place one half in a food processor with icing sugar (add a little water to form a pouring consistency).
Gently remove the individual cheesecakes from the ramekins using the cling film to help you. Place on individual serving plates. Pour over the raspberry sauce then top with remaining whole raspberries.