Grease a 20 x 30cm slice pan. Line the base and 2 long sides with baking paper, allowing the paper to overhang the long sides.
Process biscuits in a food processor until finely crushed. Add the butter and process until combined. Press mixture firmly over the base of the prepared pan. Place in the fridge for 30 minutes to chill.
Meanwhile, drain the pineapple, reserving 60ml (¼ cup) of the juice.
Place the boiling 60ml (¼ cup) boiling water in a small bowl. Sprinkle over gelatine. Stir until gelatine dissolves. Cool for 5 minutes.
Meanwhile, use electric beaters to beat the cream cheese until smooth. Add the reserved pineapple juice, condensed milk and vanilla. Beat until combined. Add the gelatine and beat until combined. Fold in the pineapple. Tint mixture yellow with food colouring, if using.
Pour mixture over prepared base in pan. Smooth top. Place in the fridge for 6 hours or overnight until set.
Use electric beaters to beat the cream and sugar until firm peaks form. Spread evenly over the cheesecake layer. Place in the fridge for 30 minutes or until chilled.
Cut the slice into squares to serve.
