It was a wise old chef who taught me this recipe, which gives maximum results for minimum effort. You can vary the coffee flavor by substituting a different alcohol, such as rum or cognac.

Serves 4
250 g/9 oz dark chocolate, chopped
4 egg whites
Pinch of salt
30 g/2 tablespoons sugar
45 ml/3 tablespoons heavy cream
45 ml/3 tablespoons espresso coffee
45 ml/3 tablespoons Kahlua
Cocoa powder, to decorate
4 mousse pots or ramekins (175 ml/¾ cup each) 

1. Fill a small saucepan with a 3.5 cm/1 in depth of water and bring to a boil. Chop the chocolate and leave it to melt in a heatproof bowl over the boiling water.

2. Whisk the egg whites with the salt in the mixer until they hold a stiff peak, add the sugar to make a light meringue, continue beating until the whites are glossy and hold a long peak, 1-2 minutes. Don’t let the meringue wait more than 5 minutes as it will start to deflate.

3. To make the mocha mixture; bring the cream and coffee to a boil in a small pan and pour it over the chocolate. Let the mixture stand for 15 seconds, then stir until smooth. Take the bowl from the heat and stir in the Kahlua. Add about a quarter of the meringue and stir until well mixed – the heat of the chocolate will lightly cook the meringue. Add this mixture to the remaining whites and fold them together as lightly as possible. Spoon the mousse into the mousse pots or ramekins, cover, and chill for at least 2 hours until set. The mousses can be prepared and kept covered for 24 hours in the refrigerator.

4. Just before serving, top the mousse with a dusting of cocoa.