Espresso martini cheesecake

Name: Espresso martini cheesecake
Ingredients: 70g salted butter, plus extra for the tin; 100g dark chocolate digestive biscuits; 150g almond cantuccini or biscotti; 150g dark chocolate, chopped; 500g full-fat soft cheese; 180g icing sugar; 300ml double cream; 30ml espresso or strong coffee; 50ml coffee liqueur; 1 tsp vanilla bean paste, or 1 vanilla pod, split and seeds scraped out; 50ml espresso or strong coffee; 50g golden caster sugar; 200g soured cream; 30g chocolate-coated coffee beans