Set aside 200 ml of the milk in a mixing bowl.

Whisk the caramel pudding powder with 2 tablespoons of sugar and the reserved milk until smooth.

Heat the remaining milk in a saucepan until nearly boiling.

Place the remaining 8 tablespoons of sugar in a clean saucepan.

Melt the sugar over low heat until it becomes an amber caramel.

Swirl the saucepan gently instead of stirring the caramel.

Remove the caramel from the heat and carefully pour in the hot milk.

Return the saucepan to low heat and stir until the caramel dissolves.

Whisk the pudding mixture into the caramel milk.

Cook the cream while stirring until it thickens.

Cover the caramel cream directly with plastic wrap and cool completely.

Beat the softened butter into the cold caramel cream until smooth.

Whip the whipping cream until it forms firm peaks.

Add the carbonated water and briefly mix it into the whipped cream.

Arrange one layer of petit beurre biscuits in the cake dish.

Spread half of the caramel cream over the biscuits.

Spread half of the whipped cream over the caramel layer.

Repeat the biscuit, caramel cream, and whipped cream layers until all ingredients are used.

Chill the cake until the layers are firm before slicing.