Prepare cake following packet directions, using 3/4 cup cold water. Turn out onto a wire rack to cool completely.

Meanwhile, make caramel crunch Line a baking tray with baking paper. Place sugar, honey and 2 tablespoons cold water in a saucepan over low heat. Cook, stirring, for 5 to 7 minutes or until sugar has dissolved. Increase heat to medium. Cook, without stirring, brushing down sides of pan occasionally with a wet pastry brush, for 5 to 6 minutes or until light golden. Remove from heat. Stir in bicarbonate of soda. Pour mixture onto prepared tray. Set aside to cool completely.

Using the end of a rolling pin, break caramel into small pieces.

Using a serrated knife, cut cake horizontally into thirds. Place base on a plate. Top with half the cream and one-third of the caramel. Repeat with middle layer, remaining cream and half the remaining caramel. Top with cake top. Spread over frosting. Sprinkle with remaining caramel. Serve.