Cut the tops off the strawberries and chop in half. Add the strawberries to a food processor with the caster sugar and lime juice.
Blitz until completely smooth then pass the puréed strawberries through a fine sieve to remove the seeds.
Add around 1 1/2 tbsp of strawberry puree to the bottom of a champagne flute and top (carefully) with prosecco. Make sure to add the prosecco a little at a time, the acidity from the fruit with make the prosecco froth much more than normal.
Please note this recipe was tested and developed using metric measurements all imperial measurements are approximate