1.Grease 20cm x 30cm (8-inch x 12-inch) rectangular pan; line base and long sides with baking paper, extending paper 5cm (2 inches) over sides.
2.Process biscuits until fine. Add butter; process until combined. Press mixture over base of pan. Refrigerate 30 minutes.
3.To make raspberry topping; process raspberries until smooth; strain puree into small bowl, discard seeds. Stir sifted icing sugar into puree. Sprinkle gelatine over the water in small heatproof jug; stand jug in small saucepan of simmering water. Stir until gelatine dissolves. Cool 5 minutes. Stir mixture through raspberry puree.
4.Beat cream cheese and sugar in medium bowl with electric mixer until smooth. Beat in cream, extract and chocolate until combined. Stir in gelatine mixture. Pour over biscuit base.
5.Spoon raspberry topping over cream cheese mixture; swirl with a skewer. Refrigerate 3 hours or overnight before cutting.
Store slice in an airtight container in the fridge for up to 4 days.Note