9 ounces chocolate (white, milk or semi-sweet)
5 Tbsp water (or 2 Tbsp water and 3 Tbsp liqueur)
1 ½ cups heavy cream
3 egg whites
Place chocolate and water in a medium sized heat proof bowl. Bring 1 inch of water to a simmer in a wide skillet. Turn the heat off and wait 30 seconds. Set bowl of chocolate in hot water. Stir chocolate constantly until melted and smooth. Remove chocolate from heat and let cool until a small dab on your upper lip feels slightly cool, about 85F.
Meanwhile, whip the cream until soft peaks form – not too stiff. Set aside.
In a clean, dry mixing bowl, beat the egg whites until stiff but not dry. Fold one-fourth of beaten egg whites into cooled white chocolate. Scrape remaining egg whites and whipped cream on top of white chocolate mixture. Fold together until combined. Turn the mousse immediately into dessert glasses. Cover and refrigerate for up to 1 day in advance.