To make the jelly: Soak gelatine leaves in cold water and set aside. Add water, strawberries and caster sugar to a pan and bring to a simmer until soft. Strain the liquid into a jug and add gelatine leaves, stir well and leave to cool. Once cooled, slowly add the fizz to the strawberry liquid and mix carefully. Pour into moulds and leave to set in the fridge for 4-5 hours.
Meanwhile make the shortbread: Cream the butter and sugar, add the flour and cornflour and form into a dough. Leave to rest in the fridge for 30 minutes. Roll out dough to the thickness of a pound coin and cut into runds. Bake at 160°C for 10-12 minutes, sprinkle with caster sugar and leave to cool.
For the lemon cream: Add the lemon juice and zest with the icing sugar to the cream and whisk until soft peaks form. Empty cream into a piping bag.
To serve run jelly moulds under warm water and pop out onto plates. Pipe cream onto shortbreads and stack. Decorate with strawberries.