Difficulty: Easy - for beginners
1 lb semisweet chocolate
3 Tbs freshly brewed espresso
2 Tbs sweet butter
4 eggs, separated
Cut eight 6" foil squares. Make four double-thickness foil cups by folding two square thickness around the bottom half of an orange. Press the foil cup gently against the counter-top to form a flat bottom.
Break half of the chocolate into small pieces and heat in a double boiler, stirring frequently, until melted and smooth.
Paint the melted chocolate across the bottoms and up the sides of the foil cups. When all of chocolate is spread up cup sides and bottoms, place the chocolate cups in the refrigerator to set.
Put the remaining chocolate and espresso in the top of a double boiler. Melt the chocolate as before, stirring often. Mix in the butter a little at a time.
Remove the pan from the heat and whisk in the egg yolks.
Whisk the egg whites in a chilled bowl until they are stiff but not dry. Fold the egg whites into the melted chocolate mixture. When well blended, pour into a bowl and refrigerate for 3 hours or until the mousse is set.
Just before serving, gently peel the foil wrapper from the chocolate cups. Spoon 1/4of the mousse mixture into each cup.