Line the base and 2 long sides of a 20cm x 30cm slice pan with baking paper, allowing the sides to overhang. Line the base with the biscuits, cutting to fit if necessary.

Use an electric beater to beat the cream cheese in a bowl until smooth. Add the condensed milk, lemon rind and lemon juice and beat until combined. Place the gelatine and boiling water in a small bowl. Stir until gelatine dissolves. Add to the cream cheese mixture and beat until combined.

Pour half the cream cheese mixture over the biscuit. Spoon over half the lemon curd. Use a skewer to swirl. Repeat with remaining cream cheese mixture and lemon curd. Place in the fridge for 3-4 hours until set. Top with caramelised lemon, if desired. Cut into slices to serve.