Grease and line a 20cm (8”) spring form cake tin. Place the crushed biscuits in a bowl and mix in the melted butter. Press biscuit mixture into the base of the prepared tin.

Press 300g (10oz) raspberries through a nylon sieve into a jug to form a purée. Take 1 tablespoon of the purée and mix with 2 tablespoons of jam to make a softened jam. Set aside. Add 250ml of cold water to the jug of remaining purée and stir. Set aside.

Cut the Gelatine sheets into small pieces and place in a heatproof bowl. Add 60ml (4 tablespoons) of cold water and soak for ten minutes, then place over a saucepan of simmering water until dissolved.

Make up the Egg Whites as directed on pack until they have soft peaks.

Place the cream cheese, yogurt and 100g (3 ½ oz) caster sugar in a bowl and beat together until well blended. Fold in the Egg Whites and Gelatine. Spoon half of the creamy mixture over the biscuit base and drizzle with the softened jam. Spoon the remaining creamy mixture on top and scatter with the remaining raspberries. Chill for at least 4 hours until set.

Meanwhile, place the Ground Arrowroot in a small saucepan and blend with a little of the raspberry purée to make a paste. Stir in the remaining purée and sugar and gently bring to the boil, stirring until clear and thickened to make a glossy raspberry sauce. Leave to cool.

To serve, remove the cheesecake from the tin and pour over the raspberry sauce.