110g / 4oz bittersweet or semi-sweet chocolate, chopped
25g / 1oz butter
3 eggs, yolks and whites separated
50g /2oz sugar
120ml / 4 fl. oz double cream
1/2 teaspoon vanilla extract.
Place a small saucepan over low heat add the butter and chocolate and cook for 5 minutes until the butter and chocolate are melted. Mix well whilst they are melting.
STEP 2When melted, take the pan off the heat and whisk the mixture with a fork to incorporate air into the mix.
STEP 3Transfer the chocolate mixture to a bowl, and beat in the egg yolks with a whisk. Place the bowl in a refrigerator.
STEP 4Beat egg whites with half the sugar until they hold stiff peaks but are not dry. Set aside. Beat cream with the remaining sugar and vanilla until it holds soft peaks.
STEP 5Stir a couple of spoonfuls of the whites into chocolate mixture to lighten it a bit, then fold in remaining whites thoroughly but gently. Fold in the cream, and refrigerate until chilled.
STEP 6If you are in a hurry, divide mousse among six cups: it will chill much faster. Serve within a day or two of making it.