In a small bowl, combine the biscuits crumbs and melted butter until the mixture resembles the texture of the wet sand. Divide the mixture between 4 loose-bottom, lightly greased small tart tins (ours were 10cm in size) and press firmly towards the sides and the bottom of each tin. Place in the fridge, while you prepare the filling.
To make the crust:
Pour a couple of tablespoons of hot water into a small bowl and sprinkle the gelatine over it. Stir to combine and set aside.
Pour the prosecco into a small saucepan, add the cornflour and the sugar and stir gently. Cook on medium-high until prosecco is hot but not boiling and the sugar has melted. Remove from the heat. Add the gelatine and stir to combine. Set aside and allow the mixture to cool.
In a medium bowl, mix the double cream and the icing sugar until soft peaks. Add vanilla and mascarpone cheese and gently fold the mixture until combined.
Slowly pour the cooled prosecco mixture into the mascarpone mixture and stir slowly and gently until evenly combined.
Remove the tart tins with crust from the fridge. Fill each tart tin with the prosecco and mascarpone mixture and return to the fridge for at least a couple of hours or until set.
To make the filling:
Place the prosecco and sugar into a small saucepan over medium high heat. Bring to boil, and reduce the heat to medium, cooking for further 10 minutes until the mixture is thick and syrupy. Remove from the heat.
Arrange sliced strawberries on top of each tart and using a pastry brush, brush the prosecco glaze over the berries. Serve & enjoy!