Chocolate Rum Baba

Name: Chocolate Rum Baba
Yield: Makes 18
Ingredients: 150 ml (5 fl oz/⅔ cup) dark rum; 100 g (3½ oz/1 stick) unsalted butter, softened, plus extra for greasing; 60 ml (2 fl oz/¼ cup) milk; 250 g (9 oz/1½ cups) raisins, washed and drained; 1 g (a pinch) salt; 20 g (¾ oz) caster (superfine) sugar; 120 ml (4fl oz/½ cup) whipping (pouring) cream (30% butter fat); 120 ml(4 fl oz/½ cup) double (heavy) cream; 450 ml (15 fl oz/1¾ cups) water; ¼ vanilla pod, split lengthways; 230 g (8 oz/1½ cups) plain flour, sifted; 200 ml (7 fl oz/generous ¾ cup) dark rum, for drizzling; 15 g (½ oz) caster (superfine) sugar; 50 g (1¾ oz/½ cup) cocoa powder; 50 g (1¾ oz) fine dark (bittersweet) chocolate (70% cocoa solids), roughly chopped; 150 g (5½ oz) whole eggs (about 3 eggs); 20 g (¾ oz) fresh yeast; 375 g (13 oz/1⅔ cups) caster (superfine) sugar