Cassis and champagne jelly with blackcurrants

By Matt Tebbutt From Saturday Kitchen Ingredients 700ml/1¼ pint champagne or sparkling wine, plus extra to serve 50ml/2fl oz cassis 50g/1¾oz caster sugar 5 gelatine leaves, softened in cold water For the blackcurrant purée 250g/9oz blackcurrants, stalks removed 1-2 tbsp icing sugar …