60g unsalted cultured butter, at room temperature
425g dark (70% cocoa) chocolate, finely chopped
40g caster sugar
1 tsp vanilla extract
1 Tbsp dark rum
Chocolate sprinkles, to roll
Desiccated coconut, to roll
Chopped pistachios, to roll
Cocoa powder, to roll
Whisk butter until very light, then set aside. Put 300g of the chocolate in a large bowl. In a medium saucepan over a medium heat, mix cream, sugar and vanilla. Bring to a simmer.
Pour 1/2 of the cream mixture into the chocolate bowl. Mix well. Repeat 2 more times to add remaining cream mixture. Fold in rum, then whisk in butter. Spoon into a glass dish, cover with plastic wrap and chill for 1 hour.
Line an oven tray with baking paper. Remove chocolate mixture from fridge and set out for 30 minutes or until begins to soften. Spoon into a piping bag fitted with a large plain nozzle and pipe 64 small balls onto prepared tray. Freeze for 20 minutes.
Melt remaining chocolate. Dip truffles in chocolate, 1 at a time, then roll in sprinkles, coconut or pistachios. Set aside. For plain cocoa truffles, allow chocolate shell to set, then roll in cocoa powder.
Serve immediately or store in an airtight container in the fridge for up to 1 month.