Add 200g of strawberries and the strawberry jam to a food processor and blitz into a smooth puree.
In a mixing bowl, combine the yoghurt, cream cheese, vanilla essence and icing sugar. Whisk using a balloon whisk or wooden spoon until the mixture is smooth.
Crush the biscuits in a small bowl using a spoon or rolling pin. Leave some chunky pieces along with some finer crumbs.
Spoon half of the yoghurt mixture into the bottom of a freezer proof dish. Add half of the strawberry puree and swirl lightly with the back of a spoon. Sprinkle over some of the biscuit pieces and half of the diced strawberry.
Add the rest of the yoghurt on top and then the red of the strawberry puree again, swirling lightly. Add the rest of the strawberry and biscuit pieces and pop the dish into the freezer for a minimum of 4 hours, or overnight until set.
Lift the frozen yoghurt out of the freezer 30 minutes before you are ready to serve, to soften slightly.