For ganache, combine ingredients in a small heatproof bowl placed over a saucepan of simmering water until chocolate is melted. Stir until smooth then refrigerate for 3-4 hours or until firm, then roll heaped teaspoons of mixture into balls and refrigerate until required.
Combine chocolate, butter and espresso in a heatproof bowl placed over a saucepan of simmering water until melted, stir until smooth and remove from heat. Combine eggs and sugar in a separate large heatproof bowl and whisk over a saucepan of simmering water for 7-8 minutes or until thick and pale. Remove from heat, fold in chocolate mixture, sieve over flour and fold in. Refrigerate for 3-4 hours.
Preheat oven to 180C. Half-fill 6 buttered and floured 150ml-capacity metal dariole moulds with pudding mixture, place an espresso ganache ball in the centre, then top up with more pudding mixture and place on an oven tray. Bake for 7-8 minutes or until risen and just firm to the touch, stand for 5 minutes then turn onto serving plates and serve immediately with double cream.