Whisk the eggs, egg yolks and condensed milk together in a bowl until just mixed. Gradually whisk in the coffee until blended.
Strain the mixture, then pour into 6 x 125 ml (4 fl oz) greased coffee cups. Transfer the cups to a roasting tin. Pour hot water into the tin to come halfway up the sides of the cups, then bake in a preheated oven, 160°C (325°F), Gas Mark 3, for 30 minutes until just set.
Lift the cups out of the water and leave the custards to cool, then transfer to the refrigerator and chill for 4–5 hours.
Whip the cream in a bowl until it forms soft swirls. Spoon the cream over the top of the custards, dust with a little sifted cocoa powder and serve with chocolate wafer sticks.